diff --git a/backend/app/api/strategy.py b/backend/app/api/strategy.py
index 42c8df4..6e40c1c 100644
--- a/backend/app/api/strategy.py
+++ b/backend/app/api/strategy.py
@@ -118,7 +118,22 @@ def _safe(result_dict: dict) -> dict:
     return result_dict
 
 
-def _strategy_detail(s: StrategyDef, overrides: dict | None = None) -> dict:
+def _child_meta(engine: StrategyEngine | None, child_id: str) -> dict:
+    """查询子策略的可读名称与来源; engine 缺失或子策略不存在时回退为 id/unknown。"""
+    if engine is None:
+        return {"name": child_id, "source": "unknown"}
+    try:
+        child = engine.get(child_id)
+    except ValueError:
+        return {"name": child_id, "source": "unknown"}
+    return {"name": str(child.meta.get("name") or child_id), "source": child.source}
+
+
+def _strategy_detail(
+    s: StrategyDef,
+    overrides: dict | None = None,
+    engine: StrategyEngine | None = None,
+) -> dict:
     """策略详情（含用户覆盖）"""
     bf = {**s.basic_filter}
     scoring = dict(s.meta.get("scoring", {}))
@@ -165,6 +180,19 @@ def _strategy_detail(s: StrategyDef, overrides: dict | None = None) -> dict:
         "descending": s.meta.get("descending", True),
         "limit": s.meta.get("limit", 30),
         "display_limit": overrides.get("display_limit") if overrides and "display_limit" in overrides else None,
+        # 叠加策略: 子策略列表与权重(供前端展示)。override.children 可覆盖 META 固化值。
+        "composite_children": (
+            [
+                {
+                    "id": c["strategy_id"],
+                    **_child_meta(engine, c["strategy_id"]),
+                    "weight": c.get("weight", 1.0),
+                }
+                for c in (overrides.get("children") if overrides and isinstance(overrides.get("children"), list) else s.meta.get("children", []))
+            ]
+            if s.execution_backend == "composite"
+            else None
+        ),
     }
 
 
@@ -218,6 +246,21 @@ class StrategyCodeSaveRequest(BaseModel):
     description: str = ""
 
 
+class CompositeChildItem(BaseModel):
+    strategy_id: str
+    weight: float = 1.0
+
+
+class StrategyCompositeSaveRequest(BaseModel):
+    strategy_id: str
+    name: str = ""
+    description: str = ""
+    children: list[CompositeChildItem]
+    merge_mode: Literal["union", "intersect"] = "union"
+    min_confirm: int = 0
+    mode: Literal["create", "update"] = "create"
+
+
 class MonitorStartRequest(BaseModel):
     strategy_id: str
 
@@ -244,7 +287,7 @@ def list_strategies(
         sid = meta["id"]
         s = engine.get(sid)
         overrides = all_overrides.get(sid)
-        result.append(_strategy_detail(s, overrides))
+        result.append(_strategy_detail(s, overrides, engine))
     return {"strategies": result, "load_errors": engine.load_errors()}
 
 
@@ -256,7 +299,7 @@ def get_strategy(strategy_id: str, request: Request):
     except ValueError as e:
         raise HTTPException(status_code=404, detail=str(e)) from e
     overrides = strategy_config.load_override(_data_dir(request), strategy_id)
-    return _strategy_detail(s, overrides or None)
+    return _strategy_detail(s, overrides or None, engine)
 
 
 # ── 执行选股 ─────────────────────────────────────────────────────────
@@ -534,8 +577,8 @@ def _validate_strategy_id(strategy_id: str) -> str:
 
 
 def _target_dir(data_dir: Path, source: str) -> Path:
-    if source not in {"ai", "custom"}:
-        raise ValueError("target_source 必须是 ai 或 custom")
+    if source not in {"ai", "custom", "composite"}:
+        raise ValueError("target_source 必须是 ai、custom 或 composite")
     return data_dir / "strategies" / source
 
 
@@ -796,6 +839,135 @@ def save_strategy_code(req: StrategyCodeSaveRequest, request: Request):
         raise HTTPException(status_code=400, detail=str(e)) from e
 
 
+def _render_composite_code(
+    sid: str,
+    name: str,
+    description: str,
+    children: list[dict],
+    merge_mode: str,
+    min_confirm: int,
+) -> str:
+    """渲染声明式 composite 策略 .py 文件内容。
+
+    composite 不含业务代码, 仅通过 META.children 引用子策略 + EXECUTION_BACKEND 声明。
+    权重固化在 META; merge_mode/min_confirm 作为 params(可经 override 轻量调整)。
+    """
+    import json as _json
+
+    children_json = ",\n        ".join(
+        _json.dumps({"strategy_id": c["strategy_id"], "weight": c["weight"]}, ensure_ascii=False)
+        for c in children
+    )
+    safe_name = name or sid
+    return f'''"""叠加策略 {sid}（自动生成, 请勿手改业务逻辑）。"""
+META = {{
+    "id": {sid!r},
+    "name": {safe_name!r},
+    "description": {description!r},
+    "asset_types": ["stock"],
+    "timeframes": ["1d"],
+    "params": [
+        {{"id": "merge_mode", "label": "合并模式", "type": "select",
+          "options": ["union", "intersect"], "default": {merge_mode!r}}},
+        {{"id": "min_confirm", "label": "交集最少确认数", "type": "int",
+          "default": {int(min_confirm)!r}, "min": 0}},
+    ],
+    "scoring": {{}},
+    "order_by": "score",
+    "descending": True,
+    "limit": 100,
+    "children": [
+        {children_json}
+    ],
+}}
+EXECUTION_BACKEND = "composite"
+'''
+
+
+def _save_composite_strategy(req: StrategyCompositeSaveRequest, request: Request) -> dict:
+    """保存叠加策略: 渲染声明式 .py → 写盘 → reload → 校验。"""
+    sid = _validate_strategy_id(req.strategy_id)
+    if not sid.startswith("composite_"):
+        raise ValueError("叠加策略 ID 必须以 composite_ 开头")
+
+    engine = _get_engine(request)
+    data_dir = _data_dir(request)
+
+    existing: StrategyDef | None = None
+    try:
+        existing = engine.get(sid)
+    except ValueError:
+        existing = None
+
+    if req.mode == "create":
+        if existing is not None:
+            raise ValueError(f"策略 {sid} 已存在，请改用修改模式或换一个策略 ID")
+    else:  # update
+        if existing is None:
+            raise ValueError(f"策略 {sid} 不存在")
+        if existing.source == "builtin":
+            raise ValueError("内置策略不可覆盖")
+        # 只允许覆盖 composite 策略(防止把普通策略覆盖成 composite)
+        if existing.execution_backend != "composite":
+            raise ValueError("目标策略不是叠加策略，无法以叠加模式覆盖")
+
+    if not req.children:
+        raise ValueError("叠加策略至少需要一个子策略")
+
+    children = [{"strategy_id": c.strategy_id, "weight": c.weight} for c in req.children]
+    # 子策略存在性预检(给出清晰错误, 而非等到 reload 后孤儿移除的笼统报错)。
+    for c in children:
+        if not engine.has(c["strategy_id"]):
+            raise ValueError(f"子策略 {c['strategy_id']!r} 不存在")
+        try:
+            child_def = engine.get(c["strategy_id"])
+            if child_def.execution_backend == "composite":
+                raise ValueError(f"子策略 {c['strategy_id']!r} 也是叠加策略; 首版禁止嵌套叠加")
+        except ValueError:
+            raise
+
+    code = _render_composite_code(
+        sid, req.name, req.description, children, req.merge_mode, req.min_confirm
+    )
+
+    out_dir = _target_dir(data_dir, "composite")
+    out_dir.mkdir(parents=True, exist_ok=True)
+    path = out_dir / f"{sid}.py"
+    previous_code = path.read_text(encoding="utf-8") if path.exists() else None
+    path.write_text(code, encoding="utf-8")
+
+    try:
+        engine.reload()
+        loaded = engine.get(sid)
+        if loaded.file_path is None or loaded.file_path.resolve() != path.resolve():
+            raise ValueError("策略加载到了非预期文件，请检查是否存在重复 strategy_id")
+        if loaded.source != "composite":
+            raise ValueError(f"策略来源异常: 期望 composite, 实际 {loaded.source}")
+        if loaded.execution_backend != "composite":
+            raise ValueError("策略后端异常: 期望 composite")
+    except Exception as e:
+        _restore_strategy_file(path, previous_code)
+        engine.reload()
+        raise ValueError(f"叠加策略保存失败: {e}") from e
+
+    _invalidate_strategy_runtime(request)
+
+    return {
+        "ok": True,
+        "strategy_id": sid,
+        "source": "composite",
+        "path": str(path),
+    }
+
+
+@router.post("/composite/save")
+def save_composite_strategy(req: StrategyCompositeSaveRequest, request: Request):
+    try:
+        return _save_composite_strategy(req, request)
+    except Exception as e:
+        raise HTTPException(status_code=400, detail=str(e)) from e
+
+
 @router.post("/ai/save")
 async def ai_save(req: AISaveRequest, request: Request):
     try:
@@ -827,9 +999,17 @@ def delete_strategy(strategy_id: str, request: Request):
     if s.source == "builtin":
         raise HTTPException(status_code=403, detail="内置策略不可删除")
 
+    # 删除被引用的子策略会令叠加策略加载失败; 删除前 fail-closed 阻止。
+    dependents = engine.find_dependents(strategy_id)
+    if dependents:
+        raise HTTPException(
+            status_code=409,
+            detail=f"该策略被叠加策略 {dependents} 引用，请先解除引用后再删除",
+        )
+
     path = s.file_path
     data_dir = _data_dir(request)
-    if path is None or s.source not in {"custom", "ai"}:
+    if path is None or s.source not in {"custom", "ai", "composite"}:
         raise HTTPException(status_code=400, detail="策略源文件路径无效, 无法删除")
 
     try:
diff --git a/backend/app/backtest/strategy.py b/backend/app/backtest/strategy.py
index ce17fa4..b938d1a 100644
--- a/backend/app/backtest/strategy.py
+++ b/backend/app/backtest/strategy.py
@@ -598,6 +598,128 @@ class StrategyBacktestService:
             json.dumps(config.overrides or {}, sort_keys=True, ensure_ascii=False, default=str),
         )
 
+    def _resolve_composite_feature_plan(
+        self,
+        strategy: StrategyDef,
+        *,
+        params: dict,
+        basic_filter: dict,
+        overrides: dict,
+    ) -> tuple[ResolvedFeaturePlan, list[tuple[StrategyDef, dict, dict]]]:
+        """解析 composite 回测的特征计划: 所有子策略 feature_plan 的并集。
+
+        返回 (合并 feature_plan, [(子策略定义, 子params, 子pipeline_config_dict), ...])。
+        子策略必须全为 matrix_native, 否则 fail-closed(首版硬约束)。
+        """
+        from app.strategy import composite as composite_mod
+        from app.strategy.engine import _parse_composite_children
+
+        assert strategy.composite is not None
+        # 权重: override.children 优先, 否则 META 声明。
+        override_children = overrides.get("children")
+        if isinstance(override_children, list) and override_children:
+            spec = _parse_composite_children(override_children)
+            children = spec.children
+        else:
+            children = strategy.composite.children
+
+        resolver = StrategyDependencyResolver()
+        plans: list[ResolvedFeaturePlan] = []
+        resolved_children: list[tuple[StrategyDef, dict, dict]] = []
+        for child in children:
+            child_def = self.strategy_engine.get(child.strategy_id)
+            if child_def.execution_backend != "matrix_native":
+                raise ValueError(
+                    f"叠加回测暂仅支持矩阵子策略; {child.strategy_id!r} "
+                    f"是 {child_def.execution_backend}"
+                )
+            if child_def.matrix_strategy is None:
+                raise ValueError(f"子策略 {child.strategy_id!r} 未注册矩阵策略")
+            # 加载子策略的用户 override(参数/评分等), 保证回测与单独跑子策略同口径。
+            child_override: dict = {}
+            loader = getattr(self.strategy_engine, "_override_loader", None)
+            if loader is not None:
+                try:
+                    loaded = loader(child.strategy_id)
+                    if isinstance(loaded, dict):
+                        child_override = dict(loaded)
+                except Exception:  # noqa: BLE001
+                    pass
+            child_params = self.strategy_engine.resolve_params(child_def, overrides=child_override)
+            child_plan = resolver.resolve(
+                child_def,
+                params=child_params,
+                basic_filter=basic_filter,  # 统一 basic_filter(计划 §3.3)
+                entry_signals=[],
+                exit_signals=[],
+                overrides=child_override,
+            )
+            plans.append(child_plan)
+            # pipeline 用 composite 统一的 basic_filter; scoring 用子策略自己的
+            # (默认 + 用户 override), 因为子策略内部排序影响合并器的排名融合。
+            child_scoring = dict(child_def.meta.get("scoring", {}) or {})
+            if isinstance(child_override.get("scoring"), dict):
+                child_scoring.update(child_override["scoring"])
+            child_pipeline_cfg = MatrixPipelineConfig(
+                basic_filter=basic_filter,
+                scoring=child_scoring,
+                order_by=child_def.meta.get("order_by"),
+                descending=bool(child_def.meta.get("descending", True)),
+                protect_strategy_cache=False,
+            )
+            resolved_children.append((child_def, child_params, child_pipeline_cfg))
+
+        merged_plan = _merge_resolved_feature_plans(plans)
+        # composite 模块用于合并时读取权重列表(顺序对齐 resolved_children)。
+        self._composite_children_weights = [(c.strategy_id, c.weight) for c in children]
+        _ = composite_mod  # 确保模块可导入(回测时由调用方使用)
+        return merged_plan, resolved_children
+
+    def _generate_composite_signal_matrix(
+        self,
+        resolved_children: list[tuple[StrategyDef, dict, dict]],
+        market_data: MarketDataMatrix,
+        merge_mode: str,
+        min_confirm: int,
+        max_hold: int,
+        timing_ms: dict[str, float],
+    ):
+        """逐子策略计算 SignalMatrix, 再合并为单个 SignalMatrix(回测合并)。
+
+        合并语义见 app.strategy.composite.merge_signal_matrices:
+        - entry: union/intersect
+        - exit: 来源投影(每个子的 exit 仅在自己持仓窗口生效, 不串平)
+        - score: 标准化排名加权
+        """
+        from app.strategy import composite as composite_mod
+
+        t_signals = time.perf_counter()
+        sigs = []
+        for child_def, child_params, child_pipeline_cfg in resolved_children:
+            try:
+                child_sig = MatrixStrategyPipeline().run(
+                    child_def.matrix_strategy,
+                    market_data,
+                    child_params,
+                    child_pipeline_cfg,
+                )
+            except (TypeError, ValueError) as e:
+                raise ValueError(f"子策略 {child_def.meta.get('id')} 信号计算失败: {e}") from e
+            sigs.append(child_sig)
+        timing_ms["strategy_signals"] = round((time.perf_counter() - t_signals) * 1000, 1)
+
+        children_weights = getattr(self, "_composite_children_weights", None) or [
+            (cd.meta.get("id", ""), 1.0) for cd, _, _ in resolved_children
+        ]
+        return composite_mod.merge_signal_matrices(
+            market_data.shape,
+            sigs,
+            children_weights,
+            merge_mode,
+            min_confirm,
+            max_hold,
+        )
+
     def prepare_matrix_optimization(
         self,
         configs: list[StrategyBacktestConfig],
@@ -839,15 +961,23 @@ class StrategyBacktestService:
         )
 
         try:
-            feature_plan = StrategyDependencyResolver().resolve(
-                s,
-                params=params,
-                basic_filter=basic_filter,
-                entry_signals=entry_signals,
-                exit_signals=exit_signals,
-                overrides=overrides,
-                minute_fill=config.minute_fill,
-            )
+            if s.execution_backend == "composite":
+                # composite 回测: 子策略必须全为 matrix_native(否则 fail-closed),
+                # feature_plan 取所有子策略计划的并集(_merge_resolved_feature_plans)。
+                feature_plan, composite_children_resolved = self._resolve_composite_feature_plan(
+                    s, params=params, basic_filter=basic_filter, overrides=overrides
+                )
+            else:
+                composite_children_resolved = None
+                feature_plan = StrategyDependencyResolver().resolve(
+                    s,
+                    params=params,
+                    basic_filter=basic_filter,
+                    entry_signals=entry_signals,
+                    exit_signals=exit_signals,
+                    overrides=overrides,
+                    minute_fill=config.minute_fill,
+                )
         except ValueError as e:
             return _err(str(e))
 
@@ -887,7 +1017,7 @@ class StrategyBacktestService:
             matrix_data_cache_status = prepared.market_data.cache_status
             matrix_data_cache_hit = matrix_data_cache_status in {"exact", "covering"}
             matrix_data_cache_timing_ms = prepared.market_data.cache_timing_ms
-        elif s.execution_backend == "matrix_native":
+        elif s.execution_backend in ("matrix_native", "composite"):
             t_load = time.perf_counter()
             max_hold_for_profile = self._override_value(
                 overrides,
@@ -985,7 +1115,89 @@ class StrategyBacktestService:
         t_signal = time.perf_counter()
         selection_stats: dict[str, int | bool]
 
-        if s.execution_backend == "matrix_native":
+        if s.execution_backend == "composite":
+            # composite 回测信号生成: 复用 matrix 数据加载, 逐子策略算信号后合并。
+            # 退出采用来源投影(composite.merge_signal_matrices), 不串平其他子策略仓位。
+            if composite_children_resolved is None:
+                return _err("叠加策略子策略解析失败")
+            if market_data is None:
+                return _err("矩阵回测缺少基础行情矩阵")
+            entry_time_mask = self._matrix_date_range_mask(
+                market_data.timestamp_labels,
+                config.start,
+                config.end,
+            )
+            exit_time_mask = self._matrix_date_range_mask(
+                market_data.timestamp_labels,
+                config.start,
+                load_end if config.mode == "full" else config.end,
+            )
+            sim_time_mask = self._matrix_date_range_mask(
+                market_data.timestamp_labels,
+                config.start,
+                sim_end,
+            )
+            time_ids = np.flatnonzero(sim_time_mask)
+            if time_ids.size == 0:
+                return _err("正式回测区间内无数据")
+            start_id = int(time_ids[0])
+            stop_id = int(time_ids[-1]) + 1
+            panel_rows = int(np.isfinite(market_data.close[start_id:stop_id]).sum())
+            panel_columns = len(feature_plan.matrix_columns)
+            reference_price = (
+                rolling_mean(market_data.close, 5)[start_id:stop_id]
+                if matcher_config.minute_fill
+                else None
+            )
+
+            merge_mode = str(params.get("merge_mode") or "union")
+            min_confirm = int(params.get("min_confirm") or 0)
+            # max_hold 用于退出投影窗口封顶; 无值时给一个足够大的兜底(仅靠信号退出)。
+            composite_max_hold = max(int(max_hold_days or 0), 1) if max_hold_days else 250
+            try:
+                signal_matrix = self._generate_composite_signal_matrix(
+                    composite_children_resolved,
+                    market_data,
+                    merge_mode,
+                    min_confirm,
+                    composite_max_hold,
+                    timing_ms,
+                )
+            except ValueError as e:
+                return _err(str(e))
+
+            sim_market_data = slice_market_data_matrix(market_data, start_id, stop_id)
+            sim_signal_matrix = slice_signal_matrix(signal_matrix, start_id, stop_id)
+            sim_signal_matrix = apply_time_masks(
+                sim_signal_matrix,
+                entry_time_mask[start_id:stop_id],
+                exit_time_mask[start_id:stop_id],
+            )
+            timing_ms["signals_score"] = round((time.perf_counter() - t_signal) * 1000, 1)
+            if not sim_signal_matrix.entry.any():
+                return _err("在指定区间内未产生买入信号")
+
+            raw_candidates = int(sim_signal_matrix.entry.sum())
+            selection_stats = {
+                "strategy_matches": raw_candidates,
+                "entry_candidates": raw_candidates,
+                "entry_trigger_filtered": 0,
+                "entry_trigger_enabled": False,
+            }
+            del market_data, signal_matrix
+
+            t_matrix = time.perf_counter()
+            market_matrix = build_market_matrix_from_signals(
+                sim_market_data,
+                sim_signal_matrix,
+                entry_delay_bars=1 if matcher_config.entry_fill == "open_t+1" else 0,
+                exit_delay_bars=1 if matcher_config.exit_fill == "open_t+1" else 0,
+                reference_price=reference_price,
+                minute_exit_trigger=matcher_config.exit_fill == "signal_next_minute",
+            )
+            timing_ms["matrix_build"] = round((time.perf_counter() - t_matrix) * 1000, 1)
+            del sim_market_data, sim_signal_matrix
+        elif s.execution_backend == "matrix_native":
             if s.matrix_strategy is None:
                 return _err("矩阵策略未注册")
             if self._has_matrix_signal_override(s, overrides):
@@ -1227,6 +1439,19 @@ class StrategyBacktestService:
             "score_max": score_max,
             "source": s.source,
             "execution_backend": s.execution_backend,
+            **(
+                {
+                    "composite_children": [
+                        {
+                            "id": cid,
+                            "weight": cw,
+                        }
+                        for cid, cw in getattr(self, "_composite_children_weights", [])
+                    ]
+                }
+                if s.execution_backend == "composite"
+                else {}
+            ),
         } if result_policy.include_strategy_info else {}
 
         selected_stats = result_policy.select_stats(result.stats)
diff --git a/backend/app/backtest/walkforward.py b/backend/app/backtest/walkforward.py
index 0f61a1a..dfdb7c1 100644
--- a/backend/app/backtest/walkforward.py
+++ b/backend/app/backtest/walkforward.py
@@ -154,7 +154,10 @@ class WalkForwardService:
             return None
         strategy = self.strategy_engine.get(cfg.strategy_id)
         if strategy.execution_backend != "matrix_native":
-            return None
+            raise ValueError(
+                f"步进优化暂仅支持矩阵(matrix_native)策略; "
+                f"{cfg.strategy_id} 是 {strategy.execution_backend}"
+            )
 
         from app.backtest.optimizer import expand_param_grid
         from app.backtest.strategy import StrategyBacktestConfig
diff --git a/backend/app/backtest/worker.py b/backend/app/backtest/worker.py
index ba35c48..1da69c6 100644
--- a/backend/app/backtest/worker.py
+++ b/backend/app/backtest/worker.py
@@ -82,6 +82,7 @@ def _strategy_dirs(data_dir: Path) -> list[Path]:
         app_dir / "strategy" / "builtin",
         data_dir / "strategies" / "custom",
         data_dir / "strategies" / "ai",
+        data_dir / "strategies" / "composite",
     ]
 
 
@@ -165,12 +166,16 @@ def _worker_entry(task: dict[str, Any], event_queue, cancel_event) -> None:
         from app.backtest.optimizer import StrategyOptimizer
         from app.backtest.strategy import StrategyBacktestService
         from app.strategy.engine import StrategyEngine
+        from app.strategy import config as strategy_config
         from app.tickflow.repository import DataStore, KlineRepository
 
         data_dir = Path(task["data_dir"])
         store = DataStore(data_dir)
         repo = KlineRepository(store)
-        strategy_engine = StrategyEngine(strategy_dirs=_strategy_dirs(data_dir))
+        strategy_engine = StrategyEngine(
+            strategy_dirs=_strategy_dirs(data_dir),
+            override_loader=lambda sid: strategy_config.load_override(data_dir, sid),
+        )
         service = StrategyBacktestService(BacktestEngine(repo), strategy_engine)
 
         def _progress(message: dict) -> None:
diff --git a/backend/app/main.py b/backend/app/main.py
index 1f801ab..13232fc 100644
--- a/backend/app/main.py
+++ b/backend/app/main.py
@@ -141,6 +141,7 @@ async def lifespan(app: FastAPI):
 
     # 策略引擎
     from app.strategy.engine import StrategyEngine
+    from app.strategy import config as strategy_config
     from app.strategy.monitor import StrategyMonitorService
     from app.services.screener import ScreenerService
 
@@ -150,9 +151,11 @@ async def lifespan(app: FastAPI):
         Path(__file__).resolve().parent / "strategy" / "builtin",
         store.data_dir / "strategies" / "custom",
         store.data_dir / "strategies" / "ai",
+        store.data_dir / "strategies" / "composite",
     ]
     strategy_engine = StrategyEngine(
         strategy_dirs=strategy_dirs,
+        override_loader=lambda sid: strategy_config.load_override(store.data_dir, sid),
     )
     app.state.strategy_engine = strategy_engine
     logger.info("strategy engine loaded: %d strategies", len(strategy_engine.list_strategies()))
diff --git a/backend/app/strategy/composite.py b/backend/app/strategy/composite.py
new file mode 100644
index 0000000..d0877b1
--- /dev/null
+++ b/backend/app/strategy/composite.py
@@ -0,0 +1,262 @@
+"""叠加策略合并器 — 选股与回测共用的纯函数。
+
+为什么单独成模块: 选股(StrategyEngine._run_composite_strategy)和回测
+(StrategyBacktestService)都要合并子策略结果, 必须共享同一套口径, 否则会出现
+"选股与回测使用不同逻辑"的金融错误(CONTRIBUTING §5.1)。
+
+两种合并入口:
+- merge_results: 选股合并。输入各子 StrategyResult, 输出合并后的 StrategyResult。
+- merge_signal_matrices: 回测合并。输入各子 SignalMatrix, 输出合并后的 SignalMatrix。
+
+合并语义(首版):
+- entry: union=OR(entries); intersect=Σ(entries) >= min_confirm
+- score: 各子内部按 score 降序排名归一到 [0,1], 命中子策略间按权重加权。
+         排名是相对位置, 跨子策略天然可比, 不依赖各子 per-strategy 的 min-max 量纲。
+- exit(回测): 来源投影。每个子策略 i 的 exit 仅在它自己 entry 后的持仓窗口内生效,
+              避免"B 的退出信号平掉 A 的仓位"。窗口由全局 max_hold 封顶。
+
+退出投影的金融正确性: 现有撮合引擎(engine.py:993)读全局 matrix.exit, 不区分来源。
+若直接 OR(exit) 会产生"幽灵平仓"(B 把 A 选的仓位卖掉)。来源投影在合并器(撮合前)
+解决, 撮合层零改动。
+"""
+from __future__ import annotations
+
+from datetime import date
+from typing import TYPE_CHECKING
+
+import numpy as np
+
+if TYPE_CHECKING:
+    from app.strategy.engine import StrategyResult
+
+# 中性分: 子策略无 score 或单候选(无法排名)时的占位, 不污染融合结果。
+_NEUTRAL_NORM = 0.5
+
+
+def _effective_weights(
+    children_weights: list[float],
+    hits_mask: list[bool],
+) -> tuple[list[float], float]:
+    """从权重列表中筛出命中子策略的权重, 返回(命中权重列表, 命中权重总和)。"""
+    effective = [w for w, hit in zip(children_weights, hits_mask, strict=True) if hit]
+    total = sum(effective)
+    return effective, total
+
+
+def merge_results(
+    results: list[StrategyResult],
+    children_weights: list[float],
+    merge_mode: str,
+    min_confirm: int,
+    *,
+    as_of: date,
+    strategy_id: str,
+    elapsed_ms: float = 0.0,
+) -> StrategyResult:
+    """选股合并: 按 symbol 聚合各子结果, 标准化排名加权融合 score。
+
+    Args:
+        results: 各子策略的 StrategyResult(顺序与 children_weights 对齐)
+        children_weights: 各子权重(顺序对齐)
+        merge_mode: "union"(任一命中即入选) | "intersect"(至少 min_confirm 个命中)
+        min_confirm: intersect 模式下命中的最少子策略数; <=0 视为全部子策略
+        as_of / strategy_id: 合并结果归属(composite 自身)
+    """
+    from app.strategy.engine import StrategyResult
+
+    n_children = len(results)
+    if n_children == 0:
+        return StrategyResult(as_of=as_of, strategy_id=strategy_id, elapsed_ms=elapsed_ms)
+
+    # 各子的 symbol → 排名归一 score。排名基于子策略内部的原始 score 降序。
+    # norm∈[0,1], 最优标的=1。单候选或无 score 时用中性分。
+    per_child_norm: list[dict[str, float]] = []
+    per_child_symbols: list[set[str]] = []
+    for res in results:
+        symbols = set(res.scores.keys())
+        per_child_symbols.append(symbols)
+        norm: dict[str, float] = {}
+        if symbols:
+            ordered = sorted(symbols, key=lambda s: res.scores[s], reverse=True)
+            count = len(ordered)
+            for rank, sym in enumerate(ordered, start=1):
+                norm[sym] = 1 - (rank - 1) / max(count - 1, 1)
+        else:
+            # 子策略未产出 score: 命中即中性分, 不奖励也不惩罚。
+            for row in res.rows:
+                sym = str(row.get("symbol"))
+                if sym and sym not in norm:
+                    norm[sym] = _NEUTRAL_NORM
+        per_child_norm.append(norm)
+
+    # 确定入围标的集合 + 各标的的命中子策略索引。
+    universe: set[str] = set()
+    for syms in per_child_symbols:
+        universe.update(syms)
+    # 也纳入 rows 里有但 scores 里没有的标的(子策略无 score 但产出行)。
+    for res in results:
+        for row in res.rows:
+            sym = str(row.get("symbol"))
+            if sym:
+                universe.add(sym)
+
+    effective_min = max(min_confirm, 1) if min_confirm and min_confirm > 0 else n_children
+    scores: dict[str, float] = {}
+    for sym in universe:
+        hits = [i for i in range(n_children) if sym in per_child_norm[i]]
+        if not hits:
+            continue
+        if merge_mode == "intersect" and len(hits) < effective_min:
+            continue
+        weights, total_w = _effective_weights(
+            children_weights, [i in hits for i in range(n_children)]
+        )
+        if total_w <= 0:
+            # 全部权重为 0: 退化为均等。
+            total_w = float(len(hits))
+            weights = [1.0] * len(hits)
+        blended = sum(w * per_child_norm[i][sym] for i, w in zip(hits, weights, strict=True))
+        scores[sym] = round(blended / total_w * 100, 4)
+
+    total = len(scores)
+    return StrategyResult(
+        as_of=as_of,
+        strategy_id=strategy_id,
+        rows=[],
+        total=total,
+        elapsed_ms=elapsed_ms,
+        scores=scores,
+    )
+
+
+def _hold_masks_from_entries(entries: list[np.ndarray], max_hold: int) -> list[np.ndarray]:
+    """计算每个子策略的持仓窗口掩码。
+
+    hold_mask_i[t, a] = True 当且仅当存在 t' <= t 使 entry_i[t', a] 触发,
+    且 t - t' < max_hold(即仍在最长持仓期内, 未被 max_hold 强制平仓)。
+    实现用前向填充: 从每个 entry 起向前扩展 max_hold-1 个 bar 为 True。
+    """
+    if max_hold <= 0:
+        max_hold = 1
+    masks: list[np.ndarray] = []
+    for entry in entries:
+        raw = entry.astype(bool, copy=False)
+        # 对每个 asset 列, 把 True 向前传播 max_hold 个 bar。
+        # 用按行位移 OR 实现: mask[t] |= raw[t-k] for k in [0, max_hold-1]
+        mask = np.zeros_like(raw)
+        window = raw.copy()
+        mask |= window
+        for _k in range(1, max_hold):
+            window = np.roll(window, 1, axis=0)
+            window[0, :] = False  # roll 会在顶部环绕, 置零防未来泄漏
+            mask |= window
+        masks.append(mask)
+    return masks
+
+
+def merge_signal_matrices(
+    shape: tuple[int, int],
+    sigs: list,
+    children: list[tuple[str, float]],
+    merge_mode: str,
+    min_confirm: int,
+    max_hold: int,
+):
+    """回测合并: 产出合并 entry/exit/score/entry_signal_code 矩阵。
+
+    Args:
+        shape: (n_times, n_assets)
+        sigs: 各子策略 SignalMatrix(顺序与 children 对齐)
+        children: [(strategy_id, weight), ...]
+        merge_mode / min_confirm: 同 merge_results
+        max_hold: 全局最长持仓天数, 用于退出投影窗口封顶
+
+    返回合并后的 SignalMatrix。
+    """
+    from app.backtest.matrix import make_signal_matrix
+
+    n_times, n_assets = shape
+    n_children = len(sigs)
+    if n_children == 0:
+        return make_signal_matrix(shape)
+
+    # ── entry ──
+    entries = [np.asarray(s.entry, dtype=bool) for s in sigs]
+    entry_stack = np.stack(entries, axis=0)  # (n_children, n_times, n_assets)
+    if merge_mode == "intersect":
+        effective_min = max(min_confirm, 1) if min_confirm and min_confirm > 0 else n_children
+        confirm_count = entry_stack.sum(axis=0)  # (n_times, n_assets)
+        merged_entry = confirm_count >= effective_min
+    else:  # union
+        merged_entry = entry_stack.any(axis=0)
+
+    # ── exit 来源投影 ──
+    # 每个子策略的 exit 仅在自己持仓窗口内生效, 不串平其他子的仓位。
+    hold_masks = _hold_masks_from_entries(entries, max_hold)
+    merged_exit = np.zeros(shape, dtype=bool)
+    for i, s in enumerate(sigs):
+        child_exit = np.asarray(s.exit, dtype=bool)
+        merged_exit |= child_exit & hold_masks[i]
+
+    # ── score 标准化排名加权 ──
+    # 对每个 (time, asset), 在命中的子策略间按权重加权各自的内部排名归一值。
+    weights = np.array([w for _, w in children], dtype=np.float64)
+    # 预计算每个子策略、每个 time 上 asset 的排名归一。
+    norm_scores = np.zeros((n_children, n_times, n_assets), dtype=np.float64)
+    for i, s in enumerate(sigs):
+        raw = np.asarray(s.score, dtype=np.float64)
+        for t in range(n_times):
+            row = raw[t]
+            hit = entries[i][t]
+            if not hit.any():
+                continue
+            hit_idx = np.flatnonzero(hit)
+            hit_vals = row[hit_idx]
+            finite = np.isfinite(hit_vals)
+            if not finite.any():
+                norm_scores[i, t, hit_idx[finite]] = _NEUTRAL_NORM
+                continue
+            valid_idx = hit_idx[finite]
+            valid_vals = hit_vals[finite]
+            n = len(valid_idx)
+            if n <= 1:
+                norm_scores[i, t, valid_idx] = _NEUTRAL_NORM
+                continue
+            # 降序排名: 最优=1, 最差=0。
+            order = np.argsort(-valid_vals, kind="stable")
+            ranks = np.empty(n, dtype=np.float64)
+            ranks[order] = np.arange(1, n + 1, dtype=np.float64)
+            normalized = 1 - (ranks - 1) / (n - 1)
+            norm_scores[i, t, valid_idx] = normalized
+
+    hit_mask = entry_stack  # (n_children, n_times, n_assets)
+    hit_weights = np.where(hit_mask, weights.reshape(-1, 1, 1), 0.0)
+    weight_sum = hit_weights.sum(axis=0)  # (n_times, n_assets)
+    blended = (norm_scores * hit_weights).sum(axis=0)
+    safe_sum = np.where(weight_sum > 0, weight_sum, 1.0)
+    merged_score = np.where(merged_entry, blended / safe_sum, 0.0) * 100
+    merged_score = np.nan_to_num(merged_score, nan=0.0, posinf=0.0, neginf=0.0)
+
+    # ── entry_signal_code: 来源标记 ──
+    # code = 命中的第一个子策略索引; -1 表示无命中。归因用。
+    entry_codes = np.full(shape, -1, dtype=np.int16)
+    for i in range(n_children):
+        # 只给尚未标记的命中点打 code(第一个命中优先), 避免覆盖。
+        untagged = (entry_codes == -1) & entries[i]
+        entry_codes[untagged] = i
+
+    # exit_signal_code 沿用 -1(无独立信号来源); 回测按 "signal" reason 归因即可。
+    exit_codes = np.full(shape, -1, dtype=np.int16)
+
+    # entry_signal_ids 映射表: code i → "composite:child_id"
+    entry_signal_ids = tuple(f"composite:{cid}" for cid, _ in children)
+
+    return make_signal_matrix(
+        shape,
+        entry=merged_entry.astype(np.uint8),
+        exit=merged_exit.astype(np.uint8),
+        score=merged_score.astype(np.float32),
+        entry_signal_code=entry_codes,
+        exit_signal_code=exit_codes,
+        entry_signal_ids=entry_signal_ids,
+    )
diff --git a/backend/app/strategy/engine.py b/backend/app/strategy/engine.py
index ecbcc71..1d3d4c2 100644
--- a/backend/app/strategy/engine.py
+++ b/backend/app/strategy/engine.py
@@ -39,6 +39,9 @@ DEFAULT_BASIC_FILTER: dict = {
     "boards": ["沪主板", "深主板", "创业板", "科创板", "北交所"],
 }
 
+# 叠加策略硬上限：子策略数量。控制信号计算成本与字段并集膨胀，避免 OOM。
+MAX_COMPOSITE_CHILDREN = 8
+
 
 def _normalize_param_defs(params: Any) -> list[dict]:
     """把 META["params"] 归一化为标准 list[dict] (每项含 id/label/type/default).
@@ -98,6 +101,42 @@ def _normalize_param_item(item: dict) -> dict:
     return norm
 
 
+def _parse_composite_children(raw: Any) -> CompositeSpec:
+    """解析 META["children"] 为 CompositeSpec。
+
+    每项形如 {"strategy_id": "xxx", "weight": 0.4}。仅做结构和权重校验:
+    - 非空 list, 每项含合法 strategy_id 与非负 weight
+    - 数量 <= MAX_COMPOSITE_CHILDREN (超出在加载期拒绝, 避免信号计算成本爆炸)
+    子策略的存在性/非嵌套/asset_types 一致性由 _load_all 两阶段校验保证。
+    """
+    if not isinstance(raw, list) or not raw:
+        raise ValueError("composite strategy META['children'] must be a non-empty list")
+    if len(raw) > MAX_COMPOSITE_CHILDREN:
+        raise ValueError(
+            f"composite strategy children count {len(raw)} exceeds limit {MAX_COMPOSITE_CHILDREN}"
+        )
+    children: list[CompositeChild] = []
+    seen: set[str] = set()
+    for i, item in enumerate(raw):
+        if not isinstance(item, dict):
+            raise ValueError(f"composite children[{i}] must be a dict")
+        cid = item.get("strategy_id")
+        if not isinstance(cid, str) or not cid:
+            raise ValueError(f"composite children[{i}] missing non-empty 'strategy_id'")
+        if cid in seen:
+            raise ValueError(f"composite children[{i}] duplicate strategy_id {cid!r}")
+        seen.add(cid)
+        weight = item.get("weight", 1.0)
+        try:
+            weight = float(weight)
+        except (TypeError, ValueError) as e:
+            raise ValueError(f"composite children[{i}] weight must be a number") from e
+        if weight < 0:
+            raise ValueError(f"composite children[{i}] weight must be >= 0")
+        children.append(CompositeChild(strategy_id=cid, weight=weight))
+    return CompositeSpec(children=tuple(children))
+
+
 @dataclass
 class StrategyDataContext:
     """一次策略调用所需的标准数据上下文。"""
@@ -111,6 +150,25 @@ class StrategyDataContext:
     cache_key: str | None = None
 
 
+@dataclass(frozen=True)
+class CompositeChild:
+    """叠加策略的一个子策略引用。"""
+
+    strategy_id: str
+    weight: float
+
+
+@dataclass(frozen=True)
+class CompositeSpec:
+    """叠加策略的子策略声明（无业务代码，仅引用与权重）。
+
+    引用合法性与一致性由 _load_all 两阶段校验保证：子策略必须存在、
+    非嵌套、asset_types 一致、数量 ≤ MAX_COMPOSITE_CHILDREN。
+    """
+
+    children: tuple[CompositeChild, ...]
+
+
 @dataclass
 class StrategyDef:
     """加载后的策略定义（只读数据 + filter 函数引用）"""
@@ -127,11 +185,12 @@ class StrategyDef:
     filter_fn: Callable[[pl.DataFrame, dict], pl.Expr] | None
     filter_history_fn: Callable[[pl.DataFrame, dict], pl.DataFrame] | None
     lookback_days: int
-    source: str  # "builtin" | "custom" | "ai"
+    source: str  # "builtin" | "custom" | "ai" | "composite"
     required_features: frozenset[str] = field(default_factory=frozenset)
     file_path: Path | None = None
     execution_backend: str = "polars_expr"
     matrix_strategy: Any | None = None
+    composite: CompositeSpec | None = None  # 仅 backend=="composite" 时非空
 
 
 @dataclass
@@ -158,12 +217,21 @@ class StrategyEngine:
 
     _module_load_lock = threading.RLock()
 
-    def __init__(self, strategy_dirs: list[Path] | None = None):
+    def __init__(
+        self,
+        strategy_dirs: list[Path] | None = None,
+        *,
+        override_loader: Callable[[str], dict] | None = None,
+    ):
         self._strategies: dict[str, StrategyDef] = {}
         self._load_errors: list[dict] = []  # 加载失败的策略 [{file, error}]
         self._strategy_dirs = strategy_dirs or []
         self._realtime_matrices: dict[str, _RealtimeMatrixEntry] = {}
         self._realtime_matrix_lock = threading.RLock()
+        # 可选的 override 加载器: 叠加策略执行时用它查子策略的用户覆盖配置,
+        # 保证 composite 内跑子策略与单独跑子策略使用同一口径(CONTRIBUTING §5.1)。
+        # None 时(测试/无 data_dir) 子策略用默认参数, 不报错。
+        self._override_loader = override_loader
         self._load_all(retain_previous_on_error=False)
 
     # ================================================================
@@ -206,6 +274,24 @@ class StrategyEngine:
                     logger.warning("load strategy %s failed: %s", f.name, e)
                     errors.append({"file": str(f), "error": str(e)})
 
+        # 第二阶段: 校验 composite 引用合法性。
+        # _load_file 是 staticmethod, 加载单个文件时无法判断 child 是否存在;
+        # 此处已拿到全部 candidates, 可做引用、嵌套、asset_types 与数量校验。
+        # 孤儿 composite (引用不合法) 被移出 candidates 并记入 errors,
+        # 但不触发整体 reload 失败 —— 不波及其他正常策略(插件隔离原则)。
+        for sid in list(candidates):
+            strategy = candidates[sid]
+            if strategy.execution_backend != "composite" or strategy.composite is None:
+                continue
+            error = self._validate_composite_references(sid, strategy, candidates)
+            if error is not None:
+                errors.append({
+                    "file": str(strategy.file_path) if strategy.file_path else sid,
+                    "error": error,
+                })
+                candidates.pop(sid, None)
+                candidate_paths.pop(sid, None)
+
         self._load_errors = errors
         if errors and retain_previous_on_error:
             return False
@@ -219,6 +305,53 @@ class StrategyEngine:
         """返回最近一次 _load_all 中加载失败的策略 [{file, error}]。"""
         return list(self._load_errors)
 
+    @staticmethod
+    def _validate_composite_references(
+        sid: str,
+        strategy: StrategyDef,
+        candidates: dict[str, StrategyDef],
+    ) -> str | None:
+        """校验 composite 策略的引用合法性。返回错误描述或 None。
+
+        规则(首版硬约束):
+        - 每个 child 必须已加载(candidates 中存在)
+        - 禁止 composite 嵌套 composite(子策略必须是叶子)
+        - child 的 asset_types / timeframes 必须与父 composite 完全一致
+        - 数量 <= MAX_COMPOSITE_CHILDREN
+        任一不满足返回错误描述, 由 _load_all 移除该孤儿策略(不波及无辜)。
+        """
+        assert strategy.composite is not None
+        children = strategy.composite.children
+        if len(children) > MAX_COMPOSITE_CHILDREN:
+            return (
+                f"composite strategy {sid} children count {len(children)} "
+                f"exceeds limit {MAX_COMPOSITE_CHILDREN}"
+            )
+        parent_assets = list(strategy.meta.get("asset_types", ["stock"]))
+        parent_timeframes = list(strategy.meta.get("timeframes", ["1d"]))
+        for child in children:
+            child_def = candidates.get(child.strategy_id)
+            if child_def is None:
+                return f"composite strategy {sid} 引用的子策略 {child.strategy_id!r} 不存在"
+            if child_def.execution_backend == "composite":
+                return (
+                    f"composite strategy {sid} 引用的子策略 {child.strategy_id!r} "
+                    f"也是叠加策略; 首版禁止嵌套叠加"
+                )
+            child_assets = list(child_def.meta.get("asset_types", ["stock"]))
+            if not set(parent_assets).issubset(set(child_assets)):
+                return (
+                    f"composite strategy {sid} 的 asset_types {parent_assets} "
+                    f"未被子策略 {child.strategy_id!r} 完全支持(支持 {child_assets})"
+                )
+            child_timeframes = list(child_def.meta.get("timeframes", ["1d"]))
+            if not set(parent_timeframes).issubset(set(child_timeframes)):
+                return (
+                    f"composite strategy {sid} 的 timeframes {parent_timeframes} "
+                    f"未被子策略 {child.strategy_id!r} 完全支持(支持 {child_timeframes})"
+                )
+        return None
+
     @staticmethod
     def _load_file(path: Path) -> StrategyDef:
         """从 Python 文件加载策略定义"""
@@ -295,6 +428,8 @@ class StrategyEngine:
             source = "builtin"
         elif "/ai/" in normalized_path:
             source = "ai"
+        elif "/composite/" in normalized_path:
+            source = "composite"
 
         if source == "builtin" and "asset_types" not in meta:
             raise ValueError("builtin strategy META must declare asset_types")
@@ -338,7 +473,7 @@ class StrategyEngine:
                 ),
             )
         )
-        valid_backends = {"polars_expr", "matrix_native", "python_history_legacy"}
+        valid_backends = {"polars_expr", "matrix_native", "python_history_legacy", "composite"}
         if execution_backend not in valid_backends:
             raise ValueError(
                 f"unsupported execution backend {execution_backend!r}; "
@@ -346,6 +481,7 @@ class StrategyEngine:
             )
 
         matrix_strategy = getattr(mod, "MATRIX_STRATEGY", None)
+        composite_spec: CompositeSpec | None = None
         if execution_backend == "matrix_native":
             from app.backtest.matrix import MatrixStrategy
 
@@ -358,6 +494,19 @@ class StrategyEngine:
         elif execution_backend == "polars_expr":
             if filter_fn is None or filter_history_fn is not None:
                 raise ValueError("polars_expr strategy must declare only filter")
+        elif execution_backend == "composite":
+            # 叠加策略是声明式的: 不含业务代码, 仅通过 META["children"] 引用其他策略。
+            # 引用合法性(子策略存在/非嵌套/asset_types 一致/数量上限)延后到
+            # _load_all 两阶段校验 —— 因为此时注册表尚未加载完, 无法判断 child 是否存在。
+            if (
+                filter_fn is not None
+                or filter_history_fn is not None
+                or matrix_strategy is not None
+            ):
+                raise ValueError(
+                    "composite strategy must not declare filter, filter_history or MATRIX_STRATEGY"
+                )
+            composite_spec = _parse_composite_children(meta.get("children"))
         elif filter_history_fn is None or filter_fn is not None:
             raise ValueError("python_history_legacy strategy must declare only filter_history")
 
@@ -381,6 +530,7 @@ class StrategyEngine:
             file_path=path,
             execution_backend=execution_backend,
             matrix_strategy=matrix_strategy,
+            composite=composite_spec,
         )
 
     def reload(self) -> None:
@@ -432,6 +582,21 @@ class StrategyEngine:
             self._realtime_matrices.clear()
         return True
 
+    def find_dependents(self, strategy_id: str) -> list[str]:
+        """返回引用了 strategy_id 作为子策略的所有 composite 策略 id。
+
+        供删除校验使用: 删除被引用的子策略会令 composite 加载失败,
+        删除前应阻止(fail-closed)或提示用户先解除引用。策略数量通常很小,
+        线性遍历注册表即可, 无需维护反向索引。
+        """
+        dependents: list[str] = []
+        for sid, strategy in self._strategies.items():
+            if strategy.execution_backend != "composite" or strategy.composite is None:
+                continue
+            if any(c.strategy_id == strategy_id for c in strategy.composite.children):
+                dependents.append(sid)
+        return dependents
+
     @staticmethod
     def validate_context(strategy: StrategyDef, context: StrategyDataContext) -> None:
         asset_types = strategy.meta.get("asset_types", ["stock"])
@@ -500,6 +665,16 @@ class StrategyEngine:
                     required,
                     int(strategy.matrix_strategy.required_warmup_bars(params)) + 1,
                 )
+            elif strategy.execution_backend == "composite":
+                # composite 预热 = 各子策略预热的 max。
+                # 子策略已通过加载期校验(非嵌套叶子), 这里展开一层即可。
+                if strategy.composite is None:
+                    continue
+                child_ids = [c.strategy_id for c in strategy.composite.children]
+                required = max(
+                    required,
+                    self.required_history_bars(child_ids, params_map=params_map),
+                )
             elif strategy.filter_history_fn:
                 required = max(required, int(strategy.lookback_days))
         return required
@@ -646,6 +821,17 @@ class StrategyEngine:
                 started_at=t0,
             )
 
+        if s.execution_backend == "composite":
+            return self._run_composite_strategy(
+                strategy_id,
+                s,
+                context,
+                pool=pool,
+                params=params,
+                overrides=overrides,
+                started_at=t0,
+            )
+
         signal_df = context.current if context.current is not None else context.history
         if signal_df is None:
             signal_df = pl.DataFrame()
@@ -998,6 +1184,112 @@ class StrategyEngine:
             exit_signal_hits=exit_signal_hits,
         )
 
+    def _run_composite_strategy(
+        self,
+        strategy_id: str,
+        strategy: StrategyDef,
+        context: StrategyDataContext,
+        *,
+        pool: list[str] | None = None,
+        params: dict | None = None,
+        overrides: dict | None = None,
+        started_at: float,
+    ) -> StrategyResult:
+        """叠加策略选股: 调度各子策略(共享 context)→ 合并结果。
+
+        复用 run_all 共享 current/history/market, 避免各子策略重复加载数据。
+        子策略必须已在加载期通过两阶段引用校验(存在/非嵌套/asset_types 一致)。
+        """
+        from app.strategy import composite as composite_mod
+
+        assert strategy.composite is not None
+        overrides = overrides or {}
+
+        # 权重: override.children 优先(META 固化值的轻量覆盖), 否则用 META 声明。
+        override_children = overrides.get("children")
+        if isinstance(override_children, list) and override_children:
+            spec = _parse_composite_children(override_children)
+            children = spec.children
+        else:
+            children = strategy.composite.children
+
+        child_ids = [c.strategy_id for c in children]
+        child_weights = [c.weight for c in children]
+        merge_mode = str(params.get("merge_mode") or "union")
+        min_confirm = int(params.get("min_confirm") or 0)
+
+        # 子策略 override: 先加载各自保存的用户配置(参数/评分/信号等),
+        # 再叠加 composite 统一的 basic_filter(计划 §3.3, 保证候选池一致)。
+        # 这样 composite 内跑子策略与单独跑子策略使用同一口径。
+        shared_basic_filter = overrides.get("basic_filter")
+        overrides_map: dict[str, dict] = {}
+        for cid in child_ids:
+            child_override: dict = {}
+            if self._override_loader is not None:
+                try:
+                    loaded = self._override_loader(cid)
+                    if isinstance(loaded, dict):
+                        child_override = dict(loaded)
+                except Exception:  # noqa: BLE001
+                    pass
+            if shared_basic_filter:
+                child_override["basic_filter"] = shared_basic_filter
+            overrides_map[cid] = child_override
+
+        # 共享 context 跑所有子策略。run_all 内部对 matrix_native 子策略会
+        # 合并 field_columns 构建超集矩阵, 一次加载。
+        child_results = self.run_all(
+            context,
+            params_map={},
+            overrides_map=overrides_map,
+            strategy_ids=child_ids,
+        )
+        ordered_results = [child_results[cid] for cid in child_ids]
+
+        merged = composite_mod.merge_results(
+            ordered_results,
+            child_weights,
+            merge_mode,
+            min_confirm,
+            as_of=context.as_of,
+            strategy_id=strategy_id,
+        )
+
+        # 构造展示行: 按 symbol 从各子结果取首个命中的行(含 name/价格等展示字段),
+        # 融合 score。子策略间 schema 可能不同, 保留首个命中子的字段即可。
+        row_by_symbol: dict[str, dict] = {}
+        for res in ordered_results:
+            for row in res.rows:
+                sym = str(row.get("symbol"))
+                if sym and sym not in row_by_symbol and sym in merged.scores:
+                    row_by_symbol[sym] = row
+
+        order_desc = bool(strategy.meta.get("descending", True))
+        ranked_symbols = sorted(
+            merged.scores.keys(),
+            key=lambda s: merged.scores[s],
+            reverse=order_desc,
+        )
+        limit = self._result_limit(strategy, overrides)
+        if limit is not None:
+            ranked_symbols = ranked_symbols[:limit]
+
+        rows = _sanitize([
+            {**row_by_symbol[sym], "score": merged.scores[sym]}
+            for sym in ranked_symbols
+            if sym in row_by_symbol
+        ])
+        scores = {str(row["symbol"]): float(row.get("score") or 0.0) for row in rows}
+
+        return StrategyResult(
+            as_of=context.as_of,
+            strategy_id=strategy_id,
+            rows=rows,
+            total=len(rows),
+            elapsed_ms=(time.perf_counter() - started_at) * 1000,
+            scores=scores,
+        )
+
     @staticmethod
     def _matrix_signal_hits(
         active: np.ndarray,
diff --git a/backend/app/strategy/monitor.py b/backend/app/strategy/monitor.py
index ed49b78..22e73c3 100644
--- a/backend/app/strategy/monitor.py
+++ b/backend/app/strategy/monitor.py
@@ -797,6 +797,12 @@ class MonitorRuleEngine:
             as_of=cn_today(),
             current=df,
         )
+        if getattr(s, "execution_backend", "polars_expr") == "composite":
+            # 叠加策略首版不支持实时监控: 各子策略需独立预热实时矩阵, 热路径成本为 N 倍,
+            # 违反"实时热路径不得随历史数据量线性增长"约束。fail-closed 跳过本轮,
+            # /cached 端点回退到盘后 strategy_cache.json 的批量结果。
+            logger.debug("叠加策略 %s 暂不支持实时监控, 跳过", sid)
+            return []
         if getattr(s, "execution_backend", "polars_expr") == "matrix_native":
             matrix = self._active_matrix_snapshots.get(at)
             if matrix is None:
diff --git a/backend/tests/backtest/test_composite_backtest_e2e.py b/backend/tests/backtest/test_composite_backtest_e2e.py
new file mode 100644
index 0000000..94b28a8
--- /dev/null
+++ b/backend/tests/backtest/test_composite_backtest_e2e.py
@@ -0,0 +1,170 @@
+"""叠加策略回测端到端集成测试 (M2 验证)。
+
+用真实的内置 matrix_native 子策略(ma_golden_cross + macd_golden) + 合成行情 panel,
+完整跑通 StrategyBacktestService.run() 的 composite 分支:
+特征计划合并 → 超集矩阵加载 → 逐子策略信号 → 合并(退出投影) → 撮合 → 结果归因。
+
+验证两种模式(position/full)和两种合并模式(union/intersect)的关键路径。
+合成数据用上涨趋势制造金叉信号。
+"""
+from __future__ import annotations
+
+from datetime import date, timedelta
+from pathlib import Path
+
+import numpy as np
+import polars as pl
+import pytest
+
+from app.backtest.engine import BacktestEngine
+from app.backtest.matrix import build_market_data_matrix
+from app.backtest.strategy import StrategyBacktestConfig, StrategyBacktestService
+from app.strategy.engine import StrategyEngine
+
+
+def _synthetic_panel() -> pl.DataFrame:
+    """构造上涨趋势的合成 panel: 前 50 天横盘, 后 50 天上涨, 制造金叉信号。"""
+    np.random.seed(42)
+    n_days = 100
+    symbols = ["000001.SZ", "000002.SZ", "600000.SH"]
+    rows = []
+    for sym_idx, sym in enumerate(symbols):
+        base = 10.0 + sym_idx * 5
+        for t in range(n_days):
+            d = date(2025, 1, 2) + timedelta(days=int(t * 1.5))
+            if t < 50:
+                close = base + np.random.uniform(-0.3, 0.3)
+            else:
+                close = base * (1 + (t - 50) * 0.015) + np.random.uniform(-0.3, 0.3)
+            open_p = close + np.random.uniform(-0.2, 0.2)
+            high = max(open_p, close) + np.random.uniform(0.1, 0.5)
+            low = min(open_p, close) - np.random.uniform(0.1, 0.5)
+            vol = float(np.random.uniform(1e6, 5e6))
+            rows.append({
+                "symbol": sym, "date": d, "open": open_p, "high": high,
+                "low": low, "close": close, "volume": vol,
+                "raw_close": close, "raw_high": high, "raw_low": low,
+            })
+    return pl.DataFrame(rows).sort(["symbol", "date"])
+
+
+class _RepoStub:
+    def get_index_daily(self, *args, **kwargs) -> pl.DataFrame:
+        return pl.DataFrame()
+
+
+def _make_service(panel: pl.DataFrame, builtin: Path, comp_dir: Path):
+    """构造 StrategyBacktestService, 用 monkeypatch 的数据加载。"""
+    bt_engine = BacktestEngine(_RepoStub())
+
+    def _load_mdm(self, symbols, start, end, feature_plan, asset_type="stock", **kw):
+        df = panel.filter((pl.col("date") >= start) & (pl.col("date") <= end))
+        if symbols:
+            df = df.filter(pl.col("symbol").is_in(symbols))
+        cols = [c for c in sorted(set(feature_plan.base_columns)) if c in df.columns]
+        return build_market_data_matrix(df.select(cols), field_columns=feature_plan.matrix_columns)
+
+    bt_engine.load_market_data_matrix_for_backtest = _load_mdm.__get__(bt_engine)
+    strategy_engine = StrategyEngine(strategy_dirs=[builtin, comp_dir])
+    return StrategyBacktestService(bt_engine, strategy_engine)
+
+
+def _write_composite(
+    comp_dir: Path, sid: str, children: list, *, merge_mode="union", min_confirm=0
+):
+    children_repr = ", ".join(
+        f'{{"strategy_id": "{c}", "weight": {w}}}' for c, w in children
+    )
+    opts = '["union", "intersect"]'
+    params_block = (
+        f'{{"id": "merge_mode", "type": "select", '
+        f'"options": {opts}, "default": "{merge_mode}"}}, '
+        f'{{"id": "min_confirm", "type": "int", "default": {min_confirm}}}'
+    )
+    (comp_dir / f"{sid}.py").write_text(
+        f'''META = {{"id": "{sid}", "name": "{sid}", "asset_types": ["stock"], "timeframes": ["1d"],
+        "params": [{params_block}], "children": [{children_repr}]}}
+EXECUTION_BACKEND = "composite"
+''',
+        encoding="utf-8",
+    )
+
+
+@pytest.fixture
+def composite_setup(tmp_path):
+    builtin = Path(__file__).resolve().parents[2] / "app" / "strategy" / "builtin"
+    comp_dir = tmp_path / "composite"
+    comp_dir.mkdir(parents=True)
+    _write_composite(comp_dir, "custom_e2e_blend", [("ma_golden_cross", 0.5), ("macd_golden", 0.5)])
+    panel = _synthetic_panel()
+    svc = _make_service(panel, builtin, comp_dir)
+    return svc, comp_dir
+
+
+def test_composite_backtest_position_mode(composite_setup):
+    """position 模式: composite 回测产出交易、净值曲线和归因。"""
+    svc, _ = composite_setup
+    cfg = StrategyBacktestConfig(
+        strategy_id="custom_e2e_blend", symbols=None,
+        start=date(2025, 2, 1), end=date(2025, 5, 1),
+        mode="position", max_positions=5, holding_days=10,
+        overrides={"basic_filter": {"enabled": False}},
+    )
+    result = svc.run(cfg)
+    assert result.error is None, f"回测失败: {result.error}"
+    assert len(result.trades) > 0, "应产出交易"
+    assert len(result.equity_curve) > 0, "应有净值曲线"
+    assert result.strategy_info is not None
+    children = result.strategy_info.get("composite_children")
+    assert children is not None and len(children) == 2
+    assert {c["id"] for c in children} == {"ma_golden_cross", "macd_golden"}
+
+
+def test_composite_backtest_full_mode(composite_setup):
+    """full 模式(独立候选): composite 回测能跑通。"""
+    svc, _ = composite_setup
+    cfg = StrategyBacktestConfig(
+        strategy_id="custom_e2e_blend", symbols=None,
+        start=date(2025, 2, 1), end=date(2025, 5, 1),
+        mode="full", holding_days=10,
+        overrides={"basic_filter": {"enabled": False}},
+    )
+    result = svc.run(cfg)
+    assert result.error is None, f"full 模式失败: {result.error}"
+    assert len(result.trades) > 0
+
+
+def test_composite_backtest_intersect_min1_equals_union(composite_setup):
+    """intersect min_confirm=1 应等价于 union(都产出交易)。"""
+    svc, comp_dir = composite_setup
+    _write_composite(
+        comp_dir, "custom_e2e_blend",
+        [("ma_golden_cross", 0.5), ("macd_golden", 0.5)],
+        merge_mode="intersect", min_confirm=1,
+    )
+    svc.strategy_engine.reload()
+    cfg = StrategyBacktestConfig(
+        strategy_id="custom_e2e_blend", symbols=None,
+        start=date(2025, 2, 1), end=date(2025, 5, 1),
+        mode="position", max_positions=5, holding_days=10,
+        overrides={"basic_filter": {"enabled": False}},
+    )
+    result = svc.run(cfg)
+    assert result.error is None, f"intersect 模式失败: {result.error}"
+    assert len(result.trades) > 0, "min_confirm=1 应产出交易(等价 union)"
+
+
+def test_worker_strategy_dirs_includes_composite(tmp_path):
+    """回归: 回测 worker 子进程重建引擎时必须扫描 composite 目录。
+
+    缺陷历史: worker._strategy_dirs 曾遗漏 composite 目录, 导致回测子进程
+    找不到 composite 策略(报 unknown strategy)。main.py 与 worker.py 必须一致。
+    """
+    from app.backtest.worker import _strategy_dirs
+
+    dirs = _strategy_dirs(tmp_path)
+    dir_names = [d.name for d in dirs]
+    assert "builtin" in dir_names
+    assert "composite" in dir_names, f"worker._strategy_dirs 缺 composite 目录: {dir_names}"
+    assert "custom" in dir_names
+    assert "ai" in dir_names
diff --git a/backend/tests/test_composite_override.py b/backend/tests/test_composite_override.py
new file mode 100644
index 0000000..b8cf58e
--- /dev/null
+++ b/backend/tests/test_composite_override.py
@@ -0,0 +1,124 @@
+"""叠加策略子策略 override 透传测试。
+
+验证修复: composite 执行时子策略应加载用户保存的 override(参数/评分等),
+否则 composite 内跑子策略与单独跑子策略使用不同口径(CONTRIBUTING §5.1)。
+
+场景: 子策略 filter 用 params["min_close"] 阈值。
+- 默认 min_close=0 → 全选
+- override 改 min_close=100 → 只选 close>100 的标的
+验证 composite(引用该子策略)在有 override_loader 时使用 override 后的阈值。
+"""
+from __future__ import annotations
+
+from datetime import date
+
+import polars as pl
+
+from app.strategy.engine import StrategyDataContext, StrategyEngine
+
+
+def _param_filter_code(strategy_id: str) -> str:
+    """子策略: filter 用 params["min_close"] 阈值, 命中 close > min_close。"""
+    return f'''import polars as pl
+META = {{
+    "id": "{strategy_id}",
+    "name": "{strategy_id}",
+    "asset_types": ["stock"],
+    "timeframes": ["1d"],
+    "params": [{{"id": "min_close", "type": "float", "default": 0}}],
+}}
+EXECUTION_BACKEND = "polars_expr"
+def filter(df, params):
+    return pl.col("close") > params.get("min_close", 0)
+'''
+
+
+def _composite_code(strategy_id: str, child_id: str) -> str:
+    return f'''META = {{
+    "id": "{strategy_id}",
+    "name": "{strategy_id}",
+    "asset_types": ["stock"],
+    "timeframes": ["1d"],
+    "params": [],
+    "children": [{{"strategy_id": "{child_id}", "weight": 1.0}}],
+}}
+EXECUTION_BACKEND = "composite"
+'''
+
+
+def _panel() -> pl.DataFrame:
+    return pl.DataFrame({
+        "symbol": ["LOW.SZ", "HIGH.SH"],
+        "date": [date(2026, 1, 2)] * 2,
+        "close": [10.0, 200.0],
+    })
+
+
+def test_composite_child_uses_default_params_without_loader(tmp_path):
+    """无 override_loader 时, 子策略用默认参数(min_close=0 → 全选)。"""
+    custom_dir = tmp_path / "strategies" / "custom"
+    comp_dir = tmp_path / "strategies" / "composite"
+    custom_dir.mkdir(parents=True)
+    comp_dir.mkdir(parents=True)
+    (custom_dir / "thresh.py").write_text(_param_filter_code("thresh"), encoding="utf-8")
+    (comp_dir / "composite_blend.py").write_text(_composite_code("composite_blend", "thresh"), encoding="utf-8")
+
+    engine = StrategyEngine(strategy_dirs=[custom_dir, comp_dir])  # 无 override_loader
+    ctx = StrategyDataContext(
+        asset_type="stock", timeframe="1d", as_of=date(2026, 1, 2),
+        current=_panel(),
+    )
+    result = engine.run("composite_blend", ctx, overrides={"basic_filter": {"enabled": False}})
+    # 默认 min_close=0 → 两个标的都命中
+    assert {"LOW.SZ", "HIGH.SH"} == {r["symbol"] for r in result.rows}
+
+
+def test_composite_child_uses_override_params_with_loader(tmp_path):
+    """有 override_loader 时, 子策略用用户 override 的参数(min_close=100 → 只选 HIGH)。"""
+    custom_dir = tmp_path / "strategies" / "custom"
+    comp_dir = tmp_path / "strategies" / "composite"
+    custom_dir.mkdir(parents=True)
+    comp_dir.mkdir(parents=True)
+    (custom_dir / "thresh.py").write_text(_param_filter_code("thresh"), encoding="utf-8")
+    (comp_dir / "composite_blend.py").write_text(_composite_code("composite_blend", "thresh"), encoding="utf-8")
+
+    # override_loader 返回 thresh 的 override: min_close=100
+    overrides_store = {"thresh": {"params": {"min_close": 100}}}
+    engine = StrategyEngine(
+        strategy_dirs=[custom_dir, comp_dir],
+        override_loader=lambda sid: overrides_store.get(sid, {}),
+    )
+    ctx = StrategyDataContext(
+        asset_type="stock", timeframe="1d", as_of=date(2026, 1, 2),
+        current=_panel(),
+    )
+    result = engine.run("composite_blend", ctx, overrides={"basic_filter": {"enabled": False}})
+    # override 后 min_close=100 → 只有 HIGH.SH(close=200) 命中, LOW.SZ(close=10) 被过滤
+    symbols = {r["symbol"] for r in result.rows}
+    assert "HIGH.SH" in symbols
+    assert "LOW.SZ" not in symbols, "子策略 override 的 min_close=100 应过滤掉 close=10 的标的"
+
+
+def test_composite_child_override_loader_failure_is_safe(tmp_path):
+    """override_loader 抛异常时, composite 应安全降级(用默认参数), 不崩溃。"""
+    custom_dir = tmp_path / "strategies" / "custom"
+    comp_dir = tmp_path / "strategies" / "composite"
+    custom_dir.mkdir(parents=True)
+    comp_dir.mkdir(parents=True)
+    (custom_dir / "thresh.py").write_text(_param_filter_code("thresh"), encoding="utf-8")
+    (comp_dir / "composite_blend.py").write_text(_composite_code("composite_blend", "thresh"), encoding="utf-8")
+
+    def bad_loader(sid: str) -> dict:
+        raise OSError("disk error")
+
+    engine = StrategyEngine(
+        strategy_dirs=[custom_dir, comp_dir],
+        override_loader=bad_loader,
+    )
+    ctx = StrategyDataContext(
+        asset_type="stock", timeframe="1d", as_of=date(2026, 1, 2),
+        current=_panel(),
+    )
+    # loader 抛异常应被捕获, 用默认参数跑(全选), 不报错
+    result = engine.run("composite_blend", ctx, overrides={"basic_filter": {"enabled": False}})
+    assert result.total > 0
diff --git a/backend/tests/test_composite_strategy.py b/backend/tests/test_composite_strategy.py
new file mode 100644
index 0000000..52eb788
--- /dev/null
+++ b/backend/tests/test_composite_strategy.py
@@ -0,0 +1,545 @@
+"""叠加策略 (composite) 加载、引用校验与选股合并测试。
+
+覆盖 CONTRIBUTING §9 矩阵中的「策略」与「回测」相关最低要求:
+- 加载解析正确, source 推断为 composite
+- 引用缺失 → 移除孤儿 composite, 不波及无辜策略(插件隔离)
+- 禁止嵌套 composite、asset_types 不一致、超过上限均 fail-closed
+- find_dependents 用于删除防护
+- 选股 union / intersect 合并, 标准化排名加权融合 score
+
+子策略用 polars_expr 后端(返回 True)以便用轻量 DataFrame 验证合并逻辑,
+不依赖 matrix_native 的矩阵加载。回测矩阵路径在 M2 单独测试。
+"""
+from __future__ import annotations
+
+from datetime import date
+
+import numpy as np
+import polars as pl
+
+from app.strategy.engine import StrategyDataContext, StrategyEngine
+
+
+def _filter_strategy_code(strategy_id: str, body: str = "return pl.lit(True)") -> str:
+    """生成一个 polars_expr 策略文件(filter 始终命中全部标的)。"""
+    return f'''import polars as pl
+META = {{
+    "id": "{strategy_id}",
+    "name": "{strategy_id}",
+    "asset_types": ["stock"],
+    "timeframes": ["1d"],
+    "scoring": {{"close": 1.0}},
+}}
+EXECUTION_BACKEND = "polars_expr"
+def filter(df, params):
+    {body}
+'''
+
+
+def _composite_code(
+    strategy_id: str,
+    children: list[tuple[str, float]],
+    *,
+    name: str | None = None,
+    asset_types: list[str] | None = None,
+    merge_mode: str = "union",
+    min_confirm: int = 0,
+) -> str:
+    """生成一个声明式 composite 策略文件。"""
+    children_repr = ", ".join(
+        f'{{"strategy_id": "{cid}", "weight": {w}}}' for cid, w in children
+    )
+    ats = asset_types or ["stock"]
+    ats_repr = ", ".join(f'"{a}"' for a in ats)
+    params = (
+        f'{{"id": "merge_mode", "type": "select", '
+        f'"options": ["union", "intersect"], "default": "{merge_mode}"}}, '
+        f'{{"id": "min_confirm", "type": "int", "default": {min_confirm}}}'
+    )
+    return f'''META = {{
+    "id": "{strategy_id}",
+    "name": "{name or strategy_id}",
+    "asset_types": [{ats_repr}],
+    "timeframes": ["1d"],
+    "params": [{params}],
+    "children": [{children_repr}],
+}}
+EXECUTION_BACKEND = "composite"
+'''
+
+
+# ───────────────────────── 加载与引用校验 ─────────────────────────
+
+
+def test_composite_loads_and_infers_source(tmp_path):
+    child_dir = tmp_path / "strategies" / "custom"
+    comp_dir = tmp_path / "strategies" / "composite"
+    child_dir.mkdir(parents=True)
+    comp_dir.mkdir(parents=True)
+    (child_dir / "child_a.py").write_text(_filter_strategy_code("child_a"), encoding="utf-8")
+    (comp_dir / "custom_blend.py").write_text(
+        _composite_code("custom_blend", [("child_a", 1.0)]), encoding="utf-8"
+    )
+
+    engine = StrategyEngine(strategy_dirs=[child_dir, comp_dir])
+
+    assert engine.has("custom_blend")
+    blend = engine.get("custom_blend")
+    assert blend.execution_backend == "composite"
+    assert blend.source == "composite"
+    assert blend.composite is not None
+    assert blend.composite.children[0].strategy_id == "child_a"
+    assert engine.load_errors() == []
+
+
+def test_composite_missing_child_is_orphaned_without_blocking_others(tmp_path):
+    """引用不存在的子策略 → composite 被移除并记错, 但不影响其他正常策略。"""
+    child_dir = tmp_path / "strategies" / "custom"
+    comp_dir = tmp_path / "strategies" / "composite"
+    child_dir.mkdir(parents=True)
+    comp_dir.mkdir(parents=True)
+    (child_dir / "real_child.py").write_text(_filter_strategy_code("real_child"), encoding="utf-8")
+    # composite 引用了不存在的 ghost_child
+    (comp_dir / "orphan_blend.py").write_text(
+        _composite_code("orphan_blend", [("ghost_child", 1.0)]), encoding="utf-8"
+    )
+    # 另一个正常 composite 不受影响
+    (comp_dir / "healthy_blend.py").write_text(
+        _composite_code("healthy_blend", [("real_child", 1.0)]), encoding="utf-8"
+    )
+
+    engine = StrategyEngine(strategy_dirs=[child_dir, comp_dir])
+
+    assert not engine.has("orphan_blend")  # 孤儿被移除
+    assert engine.has("real_child")  # 子策略不受影响
+    assert engine.has("healthy_blend")  # 其他 composite 不受影响(隔离原则)
+    errors = engine.load_errors()
+    orphan_errors = [e for e in errors if "orphan_blend" in e["file"]]
+    assert len(orphan_errors) == 1
+    assert "ghost_child" in orphan_errors[0]["error"]
+
+
+def test_nested_composite_rejected(tmp_path):
+    """禁止 composite 嵌套 composite。"""
+    child_dir = tmp_path / "strategies" / "custom"
+    comp_dir = tmp_path / "strategies" / "composite"
+    child_dir.mkdir(parents=True)
+    comp_dir.mkdir(parents=True)
+    (child_dir / "leaf.py").write_text(_filter_strategy_code("leaf"), encoding="utf-8")
+    (comp_dir / "inner.py").write_text(
+        _composite_code("inner", [("leaf", 1.0)]), encoding="utf-8"
+    )
+    (comp_dir / "outer.py").write_text(
+        _composite_code("outer", [("inner", 1.0)]), encoding="utf-8"
+    )
+
+    engine = StrategyEngine(strategy_dirs=[child_dir, comp_dir])
+
+    assert engine.has("inner")  # 单层 composite 合法
+    assert not engine.has("outer")  # 嵌套被拒
+    outer_errors = [e for e in engine.load_errors() if "outer" in e["file"]]
+    assert len(outer_errors) == 1
+    assert "嵌套" in outer_errors[0]["error"] or "nested" in outer_errors[0]["error"].lower()
+
+
+def test_composite_asset_type_mismatch_rejected(tmp_path):
+    """composite 与子策略 asset_types 不一致 → fail-closed。"""
+    child_dir = tmp_path / "strategies" / "custom"
+    comp_dir = tmp_path / "strategies" / "composite"
+    child_dir.mkdir(parents=True)
+    comp_dir.mkdir(parents=True)
+    (child_dir / "etf_child.py").write_text(
+        _filter_strategy_code("etf_child"), encoding="utf-8"
+    )
+    # 子策略是 stock(默认), composite 声明 etf
+    (comp_dir / "mismatched.py").write_text(
+        _composite_code("mismatched", [("etf_child", 1.0)], asset_types=["etf"]),
+        encoding="utf-8",
+    )
+
+    engine = StrategyEngine(strategy_dirs=[child_dir, comp_dir])
+
+    assert not engine.has("mismatched")
+    errors = [e for e in engine.load_errors() if "mismatched" in e["file"]]
+    assert len(errors) == 1
+    assert "asset_types" in errors[0]["error"]
+
+
+def test_composite_asset_type_subset_is_allowed(tmp_path):
+    """子策略支持的范围 ⊇ composite 声明 → 合法(子集关系)。
+
+    内置策略常声明 ['stock','etf'], 用户叠加时只关注 stock, 不应被拒绝。
+    """
+    child_dir = tmp_path / "strategies" / "custom"
+    comp_dir = tmp_path / "strategies" / "composite"
+    child_dir.mkdir(parents=True)
+    comp_dir.mkdir(parents=True)
+    # 子策略支持 stock + etf
+    multi_code = _filter_strategy_code("multi").replace(
+        '"asset_types": ["stock"]', '"asset_types": ["stock", "etf"]'
+    )
+    (child_dir / "multi.py").write_text(multi_code, encoding="utf-8")
+    # composite 只声明 stock(子集) → 合法
+    (comp_dir / "subset_ok.py").write_text(
+        _composite_code("subset_ok", [("multi", 1.0)], asset_types=["stock"]),
+        encoding="utf-8",
+    )
+
+    engine = StrategyEngine(strategy_dirs=[child_dir, comp_dir])
+    assert engine.has("subset_ok")
+    assert engine.load_errors() == []
+
+
+def test_composite_exceeds_child_limit_rejected(tmp_path):
+    """子策略数量超过 MAX_COMPOSITE_CHILDREN → fail-closed。"""
+    from app.strategy.engine import MAX_COMPOSITE_CHILDREN
+
+    child_dir = tmp_path / "strategies" / "custom"
+    comp_dir = tmp_path / "strategies" / "composite"
+    child_dir.mkdir(parents=True)
+    comp_dir.mkdir(parents=True)
+    for i in range(MAX_COMPOSITE_CHILDREN + 1):
+        (child_dir / f"c{i}.py").write_text(_filter_strategy_code(f"c{i}"), encoding="utf-8")
+    children = [(f"c{i}", 1.0) for i in range(MAX_COMPOSITE_CHILDREN + 1)]
+    (comp_dir / "too_many.py").write_text(
+        _composite_code("too_many", children), encoding="utf-8"
+    )
+
+    engine = StrategyEngine(strategy_dirs=[child_dir, comp_dir])
+
+    assert not engine.has("too_many")
+    errors = [e for e in engine.load_errors() if "too_many" in e["file"]]
+    assert len(errors) == 1
+    assert "limit" in errors[0]["error"] or "exceed" in errors[0]["error"]
+
+
+def test_composite_with_filter_fn_rejected(tmp_path):
+    """composite 策略声明了 filter 函数 → 加载失败。"""
+    comp_dir = tmp_path / "strategies" / "composite"
+    comp_dir.mkdir(parents=True)
+    code = _composite_code("bad", []) + "def filter(df, params):\n    return pl.lit(True)\n"
+    (comp_dir / "bad.py").write_text(code, encoding="utf-8")
+
+    engine = StrategyEngine(strategy_dirs=[comp_dir])
+
+    assert not engine.has("bad")
+    assert any("bad" in e["file"] for e in engine.load_errors())
+
+
+# ───────────────────────── find_dependents ─────────────────────────
+
+
+def test_find_dependents_locates_referencing_composites(tmp_path):
+    child_dir = tmp_path / "strategies" / "custom"
+    comp_dir = tmp_path / "strategies" / "composite"
+    child_dir.mkdir(parents=True)
+    comp_dir.mkdir(parents=True)
+    (child_dir / "shared.py").write_text(_filter_strategy_code("shared"), encoding="utf-8")
+    (child_dir / "other.py").write_text(_filter_strategy_code("other"), encoding="utf-8")
+    (comp_dir / "blend_a.py").write_text(
+        _composite_code("blend_a", [("shared", 0.5), ("other", 0.5)]), encoding="utf-8"
+    )
+    (comp_dir / "blend_b.py").write_text(
+        _composite_code("blend_b", [("shared", 1.0)]), encoding="utf-8"
+    )
+
+    engine = StrategyEngine(strategy_dirs=[child_dir, comp_dir])
+
+    assert sorted(engine.find_dependents("shared")) == ["blend_a", "blend_b"]
+    assert engine.find_dependents("other") == ["blend_a"]
+    assert engine.find_dependents("nonexistent") == []
+
+
+# ───────────────────────── 选股合并 ─────────────────────────
+
+
+def _stock_panel(symbols: list[str], scores: list[float]) -> pl.DataFrame:
+    """构造一个含 close 列(用于 scoring)的轻量 panel。"""
+    return pl.DataFrame({
+        "symbol": symbols,
+        "date": [date(2026, 1, 2)] * len(symbols),
+        "close": scores,
+    })
+
+
+def test_composite_union_merge_combines_children(tmp_path):
+    """union 模式: 两个子策略命中不同标的 → 合并后包含全部。"""
+    child_dir = tmp_path / "strategies" / "custom"
+    comp_dir = tmp_path / "strategies" / "composite"
+    child_dir.mkdir(parents=True)
+    comp_dir.mkdir(parents=True)
+    # child_a 只选 000001, child_b 只选 600000
+    (child_dir / "child_a.py").write_text(
+        _filter_strategy_code("child_a", body='return pl.col("symbol") == "000001.SZ"'),
+        encoding="utf-8",
+    )
+    (child_dir / "child_b.py").write_text(
+        _filter_strategy_code("child_b", body='return pl.col("symbol") == "600000.SH"'),
+        encoding="utf-8",
+    )
+    (comp_dir / "union_blend.py").write_text(
+        _composite_code("union_blend", [("child_a", 0.5), ("child_b", 0.5)]),
+        encoding="utf-8",
+    )
+
+    engine = StrategyEngine(strategy_dirs=[child_dir, comp_dir])
+    context = StrategyDataContext(
+        asset_type="stock",
+        timeframe="1d",
+        as_of=date(2026, 1, 2),
+        current=_stock_panel(["000001.SZ", "600000.SH"], [10.0, 20.0]),
+    )
+
+    # 禁用基础过滤(测试 panel 无 amount 等列); composite 会把 basic_filter 透传给子策略
+    result = engine.run(
+        "union_blend", context, overrides={"basic_filter": {"enabled": False}}
+    )
+
+    symbols = {row["symbol"] for row in result.rows}
+    assert symbols == {"000001.SZ", "600000.SH"}
+    assert result.total == 2
+    # 合并 score 应该来自排名归一加权(两个子各命中一个, 均为各自第一 → norm=1)
+    assert all(0 < result.scores[s] <= 100 for s in result.scores)
+
+
+def test_composite_intersect_requires_min_confirm(tmp_path):
+    """intersect 模式: 只有多个子策略共同命中才入选。"""
+    child_dir = tmp_path / "strategies" / "custom"
+    comp_dir = tmp_path / "strategies" / "composite"
+    child_dir.mkdir(parents=True)
+    comp_dir.mkdir(parents=True)
+    # 两个子策略都选 000001(共振), 但 child_b 还选 600000(非共振)
+    (child_dir / "child_a.py").write_text(
+        _filter_strategy_code("child_a", body='return pl.col("symbol") == "000001.SZ"'),
+        encoding="utf-8",
+    )
+    (child_dir / "child_b.py").write_text(
+        _filter_strategy_code(
+            "child_b",
+            body='return pl.col("symbol").is_in(["000001.SZ", "600000.SH"])',
+        ),
+        encoding="utf-8",
+    )
+    (comp_dir / "intersect_blend.py").write_text(
+        _composite_code(
+            "intersect_blend",
+            [("child_a", 0.5), ("child_b", 0.5)],
+            merge_mode="intersect",
+            min_confirm=2,
+        ),
+        encoding="utf-8",
+    )
+
+    engine = StrategyEngine(strategy_dirs=[child_dir, comp_dir])
+    context = StrategyDataContext(
+        asset_type="stock",
+        timeframe="1d",
+        as_of=date(2026, 1, 2),
+        current=_stock_panel(["000001.SZ", "600000.SH"], [10.0, 20.0]),
+    )
+
+    result = engine.run(
+        "intersect_blend", context, overrides={"basic_filter": {"enabled": False}}
+    )
+
+    # 只有 000001 同时被两个子策略命中
+    symbols = {row["symbol"] for row in result.rows}
+    assert symbols == {"000001.SZ"}
+
+
+def test_composite_weighted_score_ranking(tmp_path):
+    """权重影响最终排名: 高权重子策略的最优标的应排前。"""
+    from app.strategy import composite as composite_mod
+    from app.strategy.engine import StrategyResult
+
+    # 直接测合并器: 两个子策略, 命中相同标的但内部排名不同。
+    as_of = date(2026, 1, 2)
+    res_a = StrategyResult(
+        as_of=as_of,
+        strategy_id="a",
+        scores={"X": 100.0, "Y": 50.0},  # X 优于 Y
+    )
+    res_b = StrategyResult(
+        as_of=as_of,
+        strategy_id="b",
+        scores={"X": 10.0, "Y": 90.0},  # Y 优于 X
+    )
+
+    # b 权重远大于 a → 合并后 Y 应得分更高
+    merged = composite_mod.merge_results(
+        [res_a, res_b],
+        [0.1, 0.9],
+        "union",
+        0,
+        as_of=as_of,
+        strategy_id="blend",
+    )
+    # a 中 X rank=1(norm=1), Y rank=2(norm=0)
+    # b 中 X rank=2(norm=0), Y rank=1(norm=1)
+    # X = (0.1*1 + 0.9*0)/1.0 = 0.1; Y = (0.1*0 + 0.9*1)/1.0 = 0.9
+    assert merged.scores["Y"] > merged.scores["X"]
+
+
+def test_composite_no_scores_uses_neutral(tmp_path):
+    """子策略无 score 时用中性分, 不报错也不污染。"""
+    from app.strategy import composite as composite_mod
+    from app.strategy.engine import StrategyResult
+
+    as_of = date(2026, 1, 2)
+    res = StrategyResult(
+        as_of=as_of,
+        strategy_id="a",
+        rows=[{"symbol": "X"}, {"symbol": "Y"}],
+        scores={},  # 无 score
+    )
+
+    merged = composite_mod.merge_results([res], [1.0], "union", 0, as_of=as_of, strategy_id="b")
+
+    assert set(merged.scores) == {"X", "Y"}
+    assert all(abs(s - 50.0) < 0.01 for s in merged.scores.values())  # 中性分 0.5*100
+
+
+def test_composite_empty_children_returns_empty(tmp_path):
+    """空子结果列表 → 返回空 StrategyResult。"""
+    from app.strategy import composite as composite_mod
+
+    as_of = date(2026, 1, 2)
+    merged = composite_mod.merge_results(
+        [], [], "union", 0, as_of=as_of, strategy_id="empty"
+    )
+    assert merged.total == 0
+    assert merged.scores == {}
+
+
+# ───────────────────────── 回测合并: merge_signal_matrices ─────────────────────────
+
+
+def _make_sig(shape, *, entry, exit_, score=None):
+    """构造一个轻量 SignalMatrix(用 make_signal_matrix 保证 dtype/只读)。"""
+    from app.backtest.matrix import make_signal_matrix
+
+    entry_arr = np.array(entry, dtype=np.uint8)
+    exit_arr = np.array(exit_, dtype=np.uint8)
+    score_arr = (
+        np.array(score, dtype=np.float32)
+        if score is not None
+        else np.full(shape, 50.0, dtype=np.float32)
+    )
+    return make_signal_matrix(
+        shape,
+        entry=entry_arr,
+        exit=exit_arr,
+        score=score_arr,
+    )
+
+
+def test_merge_signal_matrices_union_entry():
+    """union 模式: entry = OR(各子 entry)。"""
+    from app.strategy import composite as composite_mod
+
+    shape = (3, 2)
+    # child A 选中 asset 0; child B 选中 asset 1
+    sig_a = _make_sig(shape, entry=[[1, 0], [0, 0], [0, 0]], exit_=[[0, 0], [0, 0], [0, 0]])
+    sig_b = _make_sig(shape, entry=[[0, 1], [0, 0], [0, 0]], exit_=[[0, 0], [0, 0], [0, 0]])
+
+    merged = composite_mod.merge_signal_matrices(
+        shape, [sig_a, sig_b], [("a", 0.5), ("b", 0.5)], "union", 0, max_hold=2
+    )
+
+    assert merged.entry[0, 0] == 1  # A 选中
+    assert merged.entry[0, 1] == 1  # B 选中
+    assert merged.entry[1].sum() == 0  # 后续无新入场
+
+
+def test_merge_signal_matrices_intersect_entry():
+    """intersect 模式: 只有多个子策略同时命中才入选。"""
+    from app.strategy import composite as composite_mod
+
+    shape = (2, 2)
+    # asset 0 被两个子策略同时命中(共振); asset 1 只被 A 命中
+    sig_a = _make_sig(shape, entry=[[1, 1], [0, 0]], exit_=[[0, 0], [0, 0]])
+    sig_b = _make_sig(shape, entry=[[1, 0], [0, 0]], exit_=[[0, 0], [0, 0]])
+
+    merged = composite_mod.merge_signal_matrices(
+        shape, [sig_a, sig_b], [("a", 0.5), ("b", 0.5)], "intersect", 2, max_hold=2
+    )
+
+    assert merged.entry[0, 0] == 1  # 共振入选
+    assert merged.entry[0, 1] == 0  # 非共振排除
+
+
+def test_merge_exit_projection_prevents_cross_close():
+    """退出投影: 子策略 B 的 exit 不会平掉子策略 A 选中的仓位。
+
+    场景: A 在 t=0 买入 asset 0, max_hold=3 → A 的持仓窗口 t∈[0,2]。
+          B 没买 asset 0, 但 B 在 t=1 对 asset 0 标了 exit(模拟无关退出信号)。
+    期望: 合并 exit 在 t=1 的 asset 0 应为 0(B 未持仓, 其 exit 被投影清零)。
+    """
+    from app.strategy import composite as composite_mod
+
+    shape = (3, 1)
+    sig_a = _make_sig(shape, entry=[[1], [0], [0]], exit_=[[0], [0], [0]])
+    # B 没买 asset 0, 但在 t=1 标了 exit
+    sig_b = _make_sig(shape, entry=[[0], [0], [0]], exit_=[[0], [1], [0]])
+
+    merged = composite_mod.merge_signal_matrices(
+        shape, [sig_a, sig_b], [("a", 1.0), ("b", 1.0)], "union", 0, max_hold=3
+    )
+
+    # 关键断言: B 的 exit(t=1) 被投影清零, 因为 B 在 asset 0 没有持仓窗口
+    assert merged.exit[1, 0] == 0, "B 的退出信号不应平掉 A 的仓位"
+
+
+def test_merge_exit_respects_child_own_exit():
+    """退出投影: 子策略自己的 exit 在自己持仓窗口内有效。
+
+    场景: A 在 t=0 买入, 在 t=2 标 exit; max_hold=3。
+    期望: 合并 exit 在 t=2 为 1(A 自己的退出在其持仓窗口内, 生效)。
+    """
+    from app.strategy import composite as composite_mod
+
+    shape = (4, 1)
+    sig_a = _make_sig(shape, entry=[[1], [0], [0], [0]], exit_=[[0], [0], [1], [0]])
+
+    merged = composite_mod.merge_signal_matrices(
+        shape, [sig_a], [("a", 1.0)], "union", 0, max_hold=3
+    )
+
+    assert merged.exit[2, 0] == 1  # A 自己的 exit 在窗口内, 生效
+
+
+def test_merge_exit_max_hold_caps_window():
+    """退出投影: 持仓窗口由 max_hold 封顶; 超出窗口后 exit 不生效。
+
+    场景: A 在 t=0 买入, max_hold=2 → 窗口 t∈[0,1]。A 在 t=3 标 exit(超出窗口)。
+    期望: 合并 exit 在 t=3 为 0(超出持仓窗口, exit 无效)。
+    """
+    from app.strategy import composite as composite_mod
+
+    shape = (5, 1)
+    sig_a = _make_sig(shape, entry=[[1], [0], [0], [0], [0]], exit_=[[0], [0], [0], [1], [0]])
+
+    merged = composite_mod.merge_signal_matrices(
+        shape, [sig_a], [("a", 1.0)], "union", 0, max_hold=2
+    )
+
+    assert merged.exit[1, 0] == 0  # 窗口内 A 无 exit
+    assert merged.exit[3, 0] == 0  # 超出窗口, exit 无效
+
+
+def test_merge_entry_signal_code_records_source():
+    """合并后 entry_signal_code 标记来源子策略(归因用)。"""
+    from app.strategy import composite as composite_mod
+
+    shape = (1, 2)
+    sig_a = _make_sig(shape, entry=[[1, 0]], exit_=[[0, 0]])
+    sig_b = _make_sig(shape, entry=[[0, 1]], exit_=[[0, 0]])
+
+    merged = composite_mod.merge_signal_matrices(
+        shape, [sig_a, sig_b], [("child_a", 1.0), ("child_b", 1.0)], "union", 0, max_hold=1
+    )
+
+    # asset 0 来自 child A (code=0), asset 1 来自 child B (code=1)
+    assert merged.entry_signal_code[0, 0] == 0
+    assert merged.entry_signal_code[0, 1] == 1
+    assert merged.entry_signal_ids == ("composite:child_a", "composite:child_b")
diff --git a/backend/tests/test_composite_strategy_api.py b/backend/tests/test_composite_strategy_api.py
new file mode 100644
index 0000000..6e24d2f
--- /dev/null
+++ b/backend/tests/test_composite_strategy_api.py
@@ -0,0 +1,230 @@
+"""叠加策略 API 与删除防护测试 (M2)。
+
+覆盖:
+- _render_composite_code 渲染声明式 .py 正确
+- _save_composite_strategy 创建/更新/校验(前缀/嵌套/子策略不存在/重复创建)
+- _strategy_detail 回显 composite_children
+- delete_strategy 删除被引用子策略时 409 fail-closed
+
+复用 test_strategy_code_save.py 的 SimpleNamespace 构造模式。
+"""
+from __future__ import annotations
+
+from types import SimpleNamespace
+
+import pytest
+from fastapi import HTTPException
+
+from app.api.strategy import (
+    CompositeChildItem,
+    StrategyCompositeSaveRequest,
+    _render_composite_code,
+    _save_composite_strategy,
+    _strategy_detail,
+)
+from app.strategy.engine import StrategyEngine
+
+
+def _filter_code(strategy_id: str) -> str:
+    meta = (
+        f'{{"id": "{strategy_id}", "name": "{strategy_id}", '
+        '"asset_types": ["stock"], "timeframes": ["1d"]}'
+    )
+    return f'''import polars as pl
+META = {meta}
+EXECUTION_BACKEND = "polars_expr"
+def filter(df, params):
+    return pl.lit(True)
+'''
+
+
+def _setup_engine(tmp_path):
+    """构造含 custom + composite 目录的 engine 和假 request。"""
+    custom_dir = tmp_path / "strategies" / "custom"
+    comp_dir = tmp_path / "strategies" / "composite"
+    custom_dir.mkdir(parents=True)
+    comp_dir.mkdir(parents=True)
+    engine = StrategyEngine(strategy_dirs=[custom_dir, comp_dir])
+    repo = SimpleNamespace(store=SimpleNamespace(data_dir=tmp_path))
+    request = SimpleNamespace(
+        app=SimpleNamespace(state=SimpleNamespace(repo=repo, strategy_engine=engine))
+    )
+    return engine, request, custom_dir, comp_dir
+
+
+def _composite_req(sid, children, **kw):
+    return StrategyCompositeSaveRequest(
+        strategy_id=sid,
+        name=kw.get("name", sid),
+        description=kw.get("description", ""),
+        children=[CompositeChildItem(strategy_id=c, weight=w) for c, w in children],
+        merge_mode=kw.get("merge_mode", "union"),
+        min_confirm=kw.get("min_confirm", 0),
+        mode=kw.get("mode", "create"),
+    )
+
+
+# ───────────────────────── 渲染 ─────────────────────────
+
+
+def test_render_composite_code_contains_children_and_backend():
+    code = _render_composite_code(
+        "composite_blend", "我的叠加", "描述",
+        [{"strategy_id": "child_a", "weight": 0.4}, {"strategy_id": "child_b", "weight": 0.6}],
+        "union", 0,
+    )
+    assert 'EXECUTION_BACKEND = "composite"' in code
+    assert "composite_blend" in code
+    assert "child_a" in code
+    assert "child_b" in code
+    assert "0.4" in code
+
+
+# ───────────────────────── 保存 ─────────────────────────
+
+
+def test_save_composite_creates_and_loads(tmp_path):
+    engine, request, custom_dir, _ = _setup_engine(tmp_path)
+    (custom_dir / "child_a.py").write_text(_filter_code("child_a"), encoding="utf-8")
+    engine.reload()
+
+    result = _save_composite_strategy(
+        _composite_req("composite_blend", [("child_a", 1.0)]), request
+    )
+    assert result["ok"] is True
+    assert result["source"] == "composite"
+    assert engine.has("composite_blend")
+    blend = engine.get("composite_blend")
+    assert blend.execution_backend == "composite"
+    assert blend.composite.children[0].strategy_id == "child_a"
+
+
+def test_save_composite_rejects_missing_composite_prefix(tmp_path):
+    engine, request, custom_dir, _ = _setup_engine(tmp_path)
+    (custom_dir / "child_a.py").write_text(_filter_code("child_a"), encoding="utf-8")
+    engine.reload()
+
+    with pytest.raises(ValueError, match="composite_"):
+        _save_composite_strategy(
+            _composite_req("bad_prefix", [("child_a", 1.0)]), request
+        )
+
+
+def test_save_composite_rejects_missing_child(tmp_path):
+    _engine, request, _, _ = _setup_engine(tmp_path)
+
+    with pytest.raises(ValueError, match="不存在"):
+        _save_composite_strategy(
+            _composite_req("composite_blend", [("ghost", 1.0)]), request
+        )
+
+
+def test_save_composite_rejects_nested_composite(tmp_path):
+    engine, request, custom_dir, _comp_dir = _setup_engine(tmp_path)
+    (custom_dir / "leaf.py").write_text(_filter_code("leaf"), encoding="utf-8")
+    engine.reload()
+    # 先创建一个合法 composite
+    _save_composite_strategy(
+        _composite_req("composite_inner", [("leaf", 1.0)]), request
+    )
+
+    with pytest.raises(ValueError, match="嵌套"):
+        _save_composite_strategy(
+            _composite_req("composite_outer", [("composite_inner", 1.0)]), request
+        )
+
+
+def test_save_composite_update_mode(tmp_path):
+    engine, request, custom_dir, _ = _setup_engine(tmp_path)
+    (custom_dir / "child_a.py").write_text(_filter_code("child_a"), encoding="utf-8")
+    (custom_dir / "child_b.py").write_text(_filter_code("child_b"), encoding="utf-8")
+    engine.reload()
+    _save_composite_strategy(
+        _composite_req("composite_blend", [("child_a", 1.0)]), request
+    )
+
+    # 更新: 改子策略
+    result = _save_composite_strategy(
+        _composite_req("composite_blend", [("child_a", 0.5), ("child_b", 0.5)], mode="update"),
+        request,
+    )
+    assert result["ok"]
+    blend = engine.get("composite_blend")
+    assert {c.strategy_id for c in blend.composite.children} == {"child_a", "child_b"}
+
+
+def test_save_composite_update_rejects_non_composite(tmp_path):
+    engine, request, custom_dir, _ = _setup_engine(tmp_path)
+    # 一个普通(polars_expr)策略, 用 composite_ 前缀以通过 id 校验进入后续检查
+    (custom_dir / "composite_plain.py").write_text(_filter_code("composite_plain"), encoding="utf-8")
+    engine.reload()
+
+    with pytest.raises(ValueError, match="不是叠加策略"):
+        _save_composite_strategy(
+            _composite_req("composite_plain", [], mode="update"), request
+        )
+
+
+# ───────────────────────── _strategy_detail ─────────────────────────
+
+
+def test_strategy_detail_shows_composite_children(tmp_path):
+    engine, request, custom_dir, _ = _setup_engine(tmp_path)
+    (custom_dir / "child_a.py").write_text(_filter_code("child_a"), encoding="utf-8")
+    (custom_dir / "child_b.py").write_text(_filter_code("child_b"), encoding="utf-8")
+    engine.reload()
+    _save_composite_strategy(
+        _composite_req("composite_blend", [("child_a", 0.4), ("child_b", 0.6)]), request
+    )
+
+    detail = _strategy_detail(engine.get("composite_blend"))
+    assert detail["execution_backend"] == "composite"
+    assert detail["composite_children"] is not None
+    children_map = {c["id"]: c["weight"] for c in detail["composite_children"]}
+    assert children_map == {"child_a": 0.4, "child_b": 0.6}
+
+
+def test_strategy_detail_non_composite_has_null_children(tmp_path):
+    engine, _request, custom_dir, _ = _setup_engine(tmp_path)
+    (custom_dir / "child_a.py").write_text(_filter_code("child_a"), encoding="utf-8")
+    engine.reload()
+
+    detail = _strategy_detail(engine.get("child_a"))
+    assert detail["composite_children"] is None
+
+
+# ───────────────────────── 删除防护 ─────────────────────────
+
+
+def test_delete_referenced_child_blocked(tmp_path):
+    """删除被 composite 引用的子策略 → 409 fail-closed。"""
+    engine, request, custom_dir, _ = _setup_engine(tmp_path)
+    (custom_dir / "child_a.py").write_text(_filter_code("child_a"), encoding="utf-8")
+    engine.reload()
+    _save_composite_strategy(
+        _composite_req("composite_blend", [("child_a", 1.0)]), request
+    )
+
+    # 直接调端点函数(delete_strategy 需要 request)
+    from app.api.strategy import delete_strategy
+
+    with pytest.raises(HTTPException) as exc_info:
+        delete_strategy("child_a", request)
+    assert exc_info.value.status_code == 409
+    assert "composite_blend" in exc_info.value.detail
+
+
+def test_delete_composite_itself_succeeds(tmp_path):
+    """删除 composite 本身(不被引用)应成功。"""
+    engine, request, custom_dir, _ = _setup_engine(tmp_path)
+    (custom_dir / "child_a.py").write_text(_filter_code("child_a"), encoding="utf-8")
+    engine.reload()
+    _save_composite_strategy(
+        _composite_req("composite_blend", [("child_a", 1.0)]), request
+    )
+
+    from app.api.strategy import delete_strategy
+
+    result = delete_strategy("composite_blend", request)
+    assert result["ok"] is True
+    assert not engine.has("composite_blend")
diff --git a/frontend/src/components/monitor/RuleEditor.tsx b/frontend/src/components/monitor/RuleEditor.tsx
index 320a663..58d7639 100644
--- a/frontend/src/components/monitor/RuleEditor.tsx
+++ b/frontend/src/components/monitor/RuleEditor.tsx
@@ -36,6 +36,7 @@ const STRATEGY_SOURCE_META = {
   builtin: { label: '内置', className: 'border-accent/25 bg-accent/10 text-accent' },
   custom: { label: '自定义', className: 'border-emerald-400/25 bg-emerald-400/10 text-emerald-400' },
   ai: { label: 'AI', className: 'border-amber-400/25 bg-amber-400/10 text-amber-400' },
+  composite: { label: '叠加', className: 'border-teal-500/25 bg-teal-500/10 text-teal-400' },
 } as const
 
 const emptyRule = (preset?: Partial<MonitorRule>): MonitorRule => ({
@@ -94,7 +95,7 @@ export function RuleEditor({ rule, preset, simple, onClose, onSaved }: Props) {
   const [error, setError] = useState('')
   const [symbolQuery, setSymbolQuery] = useState('')
   const [strategyQuery, setStrategyQuery] = useState('')
-  const [strategyCategory, setStrategyCategory] = useState<'all' | 'builtin' | 'custom' | 'ai'>('all')
+  const [strategyCategory, setStrategyCategory] = useState<'all' | 'builtin' | 'custom' | 'ai' | 'composite'>('all')
   // 标的搜索资产类型: ETF 一并搜股票; 指数只搜指数; 否则只搜股票。
   const symbolAssetTypes = assetType === 'etf' ? 'stock,etf' : assetType === 'index' ? 'index' : 'stock'
   const symbolSearch = useQuery({
@@ -212,6 +213,7 @@ export function RuleEditor({ rule, preset, simple, onClose, onSaved }: Props) {
     { key: 'builtin' as const, label: '内置', count: strategyPresets.filter(strategy => strategy.source === 'builtin').length },
     { key: 'custom' as const, label: '自定义', count: strategyPresets.filter(strategy => strategy.source === 'custom').length },
     { key: 'ai' as const, label: 'AI', count: strategyPresets.filter(strategy => strategy.source === 'ai').length },
+    { key: 'composite' as const, label: '叠加', count: strategyPresets.filter(strategy => strategy.source === 'composite').length },
   ]
 
   const onSignalPickerChange = (next: string[]) => {
diff --git a/frontend/src/components/screener/CompositeStrategyDialog.tsx b/frontend/src/components/screener/CompositeStrategyDialog.tsx
new file mode 100644
index 0000000..bd0d37e
--- /dev/null
+++ b/frontend/src/components/screener/CompositeStrategyDialog.tsx
@@ -0,0 +1,351 @@
+import { useState, useMemo, useEffect, useRef } from 'react'
+import { motion, AnimatePresence } from 'framer-motion'
+import { X, Layers, Plus, Loader2, Search } from 'lucide-react'
+import { api, type ScreenerStrategy } from '@/lib/api'
+
+interface Props {
+  open: boolean
+  onClose: () => void
+  onSavedId?: (id: string) => void | Promise<void>
+  /** 编辑模式: 传入已有 composite 策略 id 时为 update, 否则 create */
+  editStrategyId?: string | null
+}
+
+interface ChildItem {
+  strategy_id: string
+  weight: number
+}
+
+const SRC_MAP: Record<string, string> = { builtin: '内置', custom: '自定义', ai: 'AI' }
+const BADGE_CLS: Record<string, string> = {
+  builtin: 'bg-accent/10 text-accent border-accent/20',
+  ai: 'bg-purple-500/10 text-purple-400 border-purple-500/20',
+  custom: 'bg-amber-400/10 text-amber-400 border-amber-400/30',
+}
+
+export function CompositeStrategyDialog({ open, onClose, onSavedId, editStrategyId }: Props) {
+  const isEdit = !!editStrategyId
+  const [name, setName] = useState('')
+  const [description, setDescription] = useState('')
+  const [strategyId, setStrategyId] = useState('')
+  const [children, setChildren] = useState<ChildItem[]>([])
+  const [mergeMode, setMergeMode] = useState<'union' | 'intersect'>('union')
+  const [minConfirm, setMinConfirm] = useState(0)
+  const [saving, setSaving] = useState(false)
+  const [error, setError] = useState('')
+  const [search, setSearch] = useState('')
+  // 记录鼠标按下时是否落在遮罩上, 避免拖选文本时鼠标移出面板导致误关。
+  const mouseDownOnBackdrop = useRef(false)
+
+  // 拉取所有可用子策略(排除 composite 自身)
+  const [available, setAvailable] = useState<ScreenerStrategy[]>([])
+  const [loadingList, setLoadingList] = useState(false)
+
+  useEffect(() => {
+    if (!open) return
+    // 重置表单
+    setName('')
+    setDescription('')
+    // 创建模式自动生成 ID(composite_ + 时间戳), 编辑模式用现有 ID
+    setStrategyId(isEdit ? (editStrategyId ?? '') : `composite_${Date.now().toString(36)}`)
+    setChildren([])
+    setMergeMode('union')
+    setMinConfirm(0)
+    setError('')
+    setSearch('')
+    setLoadingList(true)
+    api.screenerStrategies()
+      .then(data => {
+        // 排除 composite 策略(不能嵌套)
+        setAvailable((data.presets ?? []).filter(s => s.source !== 'composite'))
+      })
+      .catch(() => setAvailable([]))
+      .finally(() => setLoadingList(false))
+    // 编辑模式: 加载现有配置回显
+    if (isEdit && editStrategyId) {
+      api.strategyGet(editStrategyId)
+        .then(detail => {
+          setName(detail.name)
+          setDescription(detail.description)
+          setMergeMode((detail.params_defaults?.merge_mode as 'union' | 'intersect') ?? 'union')
+          setMinConfirm(detail.params_defaults?.min_confirm ?? 0)
+          if (detail.composite_children) {
+            setChildren(detail.composite_children.map(c => ({ strategy_id: c.id, weight: c.weight })))
+          }
+        })
+        .catch(() => {})
+    }
+  }, [open, isEdit, editStrategyId])
+
+  const filteredAvailable = useMemo(() => {
+    const keyword = search.trim().toLowerCase()
+    const selectedIds = new Set(children.map(c => c.strategy_id))
+    return available.filter(s => {
+      if (selectedIds.has(s.id)) return false
+      if (!keyword) return true
+      return s.name.toLowerCase().includes(keyword) || s.id.toLowerCase().includes(keyword)
+    })
+  }, [available, children, search])
+
+  const addChild = (s: ScreenerStrategy) => {
+    setChildren(prev => [...prev, { strategy_id: s.id, weight: 1.0 }])
+  }
+  const removeChild = (id: string) => {
+    setChildren(prev => prev.filter(c => c.strategy_id !== id))
+  }
+  const updateWeight = (id: string, weight: number) => {
+    setChildren(prev => prev.map(c => c.strategy_id === id ? { ...c, weight } : c))
+  }
+
+  const totalWeight = useMemo(
+    () => children.reduce((sum, c) => sum + (c.weight || 0), 0),
+    [children],
+  )
+
+  const normalizeWeights = () => {
+    if (totalWeight <= 0) return
+    setChildren(prev => prev.map(c => ({ ...c, weight: Math.round((c.weight / totalWeight) * 1000) / 1000 })))
+  }
+
+  const handleSave = async () => {
+    setError('')
+    if (!name.trim()) {
+      setError('请输入策略名称')
+      return
+    }
+    if (children.length === 0) {
+      setError('请至少选择一个子策略')
+      return
+    }
+    setSaving(true)
+    try {
+      const result = await api.strategySaveComposite({
+        strategy_id: isEdit ? (editStrategyId ?? '') : strategyId.trim(),
+        name: name.trim(),
+        description: description.trim(),
+        children: children.map(c => ({ strategy_id: c.strategy_id, weight: c.weight })),
+        merge_mode: mergeMode,
+        min_confirm: minConfirm,
+        mode: isEdit ? 'update' : 'create',
+      })
+      await onSavedId?.(result.strategy_id)
+      setTimeout(() => onClose(), 800)
+    } catch (e: any) {
+      setError(String(e?.message ?? '保存失败'))
+    }
+    setSaving(false)
+  }
+
+  return (
+    <AnimatePresence>
+      {open && (
+        <motion.div
+          className="fixed inset-0 z-50 flex items-center justify-center bg-black/50 p-4"
+          initial={{ opacity: 0 }}
+          animate={{ opacity: 1 }}
+          exit={{ opacity: 0 }}
+          onMouseDown={(e) => {
+            mouseDownOnBackdrop.current = e.target === e.currentTarget
+          }}
+          onClick={(e) => {
+            // 仅当按下和松开都在遮罩上才关闭, 避免面板内拖选文本误关。
+            if (mouseDownOnBackdrop.current && e.target === e.currentTarget) onClose()
+          }}
+        >
+          <motion.div
+            className="relative flex max-h-[88vh] w-full max-w-3xl flex-col overflow-hidden rounded-panel border border-border bg-base shadow-2xl"
+            initial={{ scale: 0.96, opacity: 0 }}
+            animate={{ scale: 1, opacity: 1 }}
+            exit={{ scale: 0.96, opacity: 0 }}
+            onClick={e => e.stopPropagation()}
+          >
+            {/* 头部 */}
+            <div className="flex items-center gap-2 border-b border-border px-4 py-3">
+              <Layers className="h-4 w-4 text-teal-400" />
+              <span className="text-sm font-semibold text-foreground">
+                {isEdit ? '编辑叠加策略' : '创建叠加策略'}
+              </span>
+              <span className="text-[10px] text-muted/60">
+                引用多个子策略, 合并选股与回测信号
+              </span>
+              <button onClick={onClose} className="ml-auto text-muted hover:text-foreground">
+                <X className="h-4 w-4" />
+              </button>
+            </div>
+
+            {/* 主体 */}
+            <div className="flex-1 overflow-y-auto p-4 space-y-4">
+              {/* 基本信息 */}
+              <div className="grid grid-cols-1 gap-3 sm:grid-cols-2">
+                <div>
+                  <label className="mb-1 block text-xs text-muted">策略 ID（自动生成）</label>
+                  <input
+                    value={strategyId}
+                    readOnly
+                    disabled
+                    placeholder="composite_..."
+                    className="w-full rounded-btn border border-border bg-elevated px-2 py-1.5 font-mono text-[11px] text-muted cursor-not-allowed"
+                  />
+                </div>
+                <div>
+                  <label className="mb-1 block text-xs text-muted">策略名称</label>
+                  <input
+                    value={name}
+                    onChange={e => setName(e.target.value)}
+                    placeholder="我的叠加策略"
+                    className="w-full rounded-btn border border-border bg-elevated px-2 py-1.5 text-xs text-foreground placeholder:text-muted/40"
+                  />
+                </div>
+              </div>
+              <div>
+                <label className="mb-1 block text-xs text-muted">描述（可选）</label>
+                <input
+                  value={description}
+                  onChange={e => setDescription(e.target.value)}
+                  placeholder="说明这个叠加策略的意图"
+                  className="w-full rounded-btn border border-border bg-elevated px-2 py-1.5 text-xs text-foreground placeholder:text-muted/40"
+                />
+              </div>
+
+              {/* 合并模式 */}
+              <div className="grid grid-cols-1 gap-3 sm:grid-cols-2">
+                <div>
+                  <label className="mb-1 block text-xs text-muted">合并模式</label>
+                  <select
+                    value={mergeMode}
+                    onChange={e => setMergeMode(e.target.value as 'union' | 'intersect')}
+                    className="w-full rounded-btn border border-border bg-elevated px-2 py-1.5 text-xs text-foreground"
+                  >
+                    <option value="union">并集（任一子策略命中即入选）</option>
+                    <option value="intersect">交集（至少 N 个子策略同时命中）</option>
+                  </select>
+                </div>
+                <div>
+                  <label className="mb-1 block text-xs text-muted">交集最少确认数（0=全部）</label>
+                  <input
+                    type="number"
+                    min={0}
+                    value={minConfirm}
+                    onChange={e => setMinConfirm(Math.max(0, parseInt(e.target.value) || 0))}
+                    disabled={mergeMode !== 'intersect'}
+                    className="w-full rounded-btn border border-border bg-elevated px-2 py-1.5 text-xs text-foreground disabled:opacity-50"
+                  />
+                </div>
+              </div>
+
+              {/* 已选子策略 */}
+              <div>
+                <div className="mb-1.5 flex items-center justify-between">
+                  <label className="text-xs font-medium text-foreground">
+                    子策略（{children.length}）
+                  </label>
+                  <span className="text-[10px] text-muted flex items-center gap-1.5">
+                    权重总和: {totalWeight.toFixed(2)}
+                    {totalWeight > 0 && Math.abs(totalWeight - 1) > 0.001 && (
+                      <button onClick={normalizeWeights} className="text-teal-400 hover:text-teal-300 underline underline-offset-2">归一</button>
+                    )}
+                  </span>
+                </div>
+                <div className="space-y-1.5">
+                  {children.length === 0 && (
+                    <div className="rounded-btn border border-dashed border-border px-3 py-4 text-center text-xs text-muted">
+                      从下方列表选择子策略
+                    </div>
+                  )}
+                  {children.map(c => {
+                    const s = available.find(a => a.id === c.strategy_id)
+                    return (
+                      <div key={c.strategy_id} className="flex items-center gap-2 rounded-btn border border-border bg-elevated px-2 py-1.5">
+                        <span className="flex-1 truncate text-xs text-foreground">{s?.name ?? c.strategy_id}</span>
+                        {s?.source && (
+                          <span className={`rounded border px-1 text-[8px] ${BADGE_CLS[s.source] ?? ''}`}>
+                            {SRC_MAP[s.source] ?? s.source}
+                          </span>
+                        )}
+                        <input
+                          type="number"
+                          step={0.05}
+                          min={0}
+                          value={c.weight}
+                          onChange={e => updateWeight(c.strategy_id, parseFloat(e.target.value) || 0)}
+                          className="w-16 rounded border border-border bg-base px-1.5 py-0.5 text-[11px] text-foreground"
+                        />
+                        <button onClick={() => removeChild(c.strategy_id)} className="text-danger/60 hover:text-danger">
+                          <X className="h-3 w-3" />
+                        </button>
+                      </div>
+                    )
+                  })}
+                </div>
+              </div>
+
+              {/* 可选子策略 */}
+              <div>
+                <label className="mb-1.5 block text-xs font-medium text-foreground">可选策略</label>
+                <div className="relative mb-1.5">
+                  <Search className="absolute left-2 top-1/2 h-3 w-3 -translate-y-1/2 text-muted/50" />
+                  <input
+                    value={search}
+                    onChange={e => setSearch(e.target.value)}
+                    placeholder="搜索策略名称或 ID"
+                    className="w-full rounded-btn border border-border bg-elevated py-1.5 pl-7 pr-2 text-xs text-foreground placeholder:text-muted/40"
+                  />
+                </div>
+                <div className="max-h-48 space-y-1 overflow-y-auto rounded-btn border border-border bg-elevated p-1.5">
+                  {loadingList && (
+                    <div className="flex items-center justify-center gap-1.5 py-3 text-xs text-muted">
+                      <Loader2 className="h-3 w-3 animate-spin" /> 加载中
+                    </div>
+                  )}
+                  {!loadingList && filteredAvailable.length === 0 && (
+                    <div className="py-3 text-center text-xs text-muted">无可用策略</div>
+                  )}
+                  {filteredAvailable.map(s => (
+                    <button
+                      key={s.id}
+                      onClick={() => addChild(s)}
+                      className="flex w-full items-center gap-1.5 rounded px-2 py-1 text-left text-xs text-foreground hover:bg-accent/10"
+                    >
+                      <Plus className="h-3 w-3 shrink-0 text-teal-400" />
+                      <span className="flex-1 truncate">{s.name}</span>
+                      {s.source && (
+                        <span className={`rounded border px-1 text-[8px] ${BADGE_CLS[s.source] ?? ''}`}>
+                          {SRC_MAP[s.source] ?? s.source}
+                        </span>
+                      )}
+                      <span className="font-mono text-[9px] text-muted/50">{s.id}</span>
+                    </button>
+                  ))}
+                </div>
+              </div>
+
+              {error && (
+                <div className="rounded-btn border border-danger/30 bg-danger/10 px-3 py-2 text-xs text-danger">
+                  {error}
+                </div>
+              )}
+            </div>
+
+            {/* 底部 */}
+            <div className="flex items-center justify-end gap-2 border-t border-border px-4 py-3">
+              <button
+                onClick={onClose}
+                className="rounded-btn border border-border px-3 py-1.5 text-xs text-muted hover:text-foreground"
+              >
+                取消
+              </button>
+              <button
+                onClick={handleSave}
+                disabled={saving}
+                className="inline-flex items-center gap-1.5 rounded-btn bg-teal-500/15 px-3 py-1.5 text-xs font-medium text-teal-400 border border-teal-500/30 hover:bg-teal-500/25 disabled:opacity-50"
+              >
+                {saving && <Loader2 className="h-3 w-3 animate-spin" />}
+                {isEdit ? '保存修改' : '创建'}
+              </button>
+            </div>
+          </motion.div>
+        </motion.div>
+      )}
+    </AnimatePresence>
+  )
+}
diff --git a/frontend/src/components/screener/StrategyCard.tsx b/frontend/src/components/screener/StrategyCard.tsx
index 9dc8547..f2efbff 100644
--- a/frontend/src/components/screener/StrategyCard.tsx
+++ b/frontend/src/components/screener/StrategyCard.tsx
@@ -63,11 +63,12 @@ export function cardWrapCls(size: CardSize): string {
 
 // ===== 来源标签 =====
 
-const SRC_MAP: Record<string, string> = { builtin: '内置', custom: '自定义', ai: 'AI' }
+const SRC_MAP: Record<string, string> = { builtin: '内置', custom: '自定义', ai: 'AI', composite: '叠加' }
 const BADGE_CLS_MAP: Record<string, string> = {
   builtin: 'bg-secondary/10 text-muted border-border',
   ai: 'bg-purple-500/10 text-purple-400 border-purple-500/30',
   custom: 'bg-amber-400/10 text-amber-400 border-amber-400/30',
+  composite: 'bg-teal-500/10 text-teal-400 border-teal-500/30',
 }
 
 // ===== 策略卡片 =====
diff --git a/frontend/src/components/screener/StrategyPoolDialog.tsx b/frontend/src/components/screener/StrategyPoolDialog.tsx
index 9eae1f5..d6dcc21 100644
--- a/frontend/src/components/screener/StrategyPoolDialog.tsx
+++ b/frontend/src/components/screener/StrategyPoolDialog.tsx
@@ -2,6 +2,7 @@ import { useState, useMemo, useEffect, useCallback, useRef } from 'react'
 import { motion, AnimatePresence, Reorder } from 'framer-motion'
 import { X, Plus, GripVertical, Upload, Loader2 } from 'lucide-react'
 import { api, type StrategyDetail } from '@/lib/api'
+import { useDialogBackdrop } from '@/lib/useDialogBackdrop'
 
 interface Props {
   pool: string[]
@@ -42,6 +43,7 @@ function fileStem(name: string): string {
 }
 
 export function StrategyPoolDialog({ pool, onConfirm, onClose }: Props) {
+  const backdrop = useDialogBackdrop(onClose)
   // 草稿状态: 打开时从 pool 复制, 操作只改草稿, 点确定才提交
   const [draftPool, setDraftPool] = useState<string[]>(() => [...pool])
   const [allStrategies, setAllStrategies] = useState<StrategyDetail[]>([])
@@ -121,7 +123,7 @@ export function StrategyPoolDialog({ pool, onConfirm, onClose }: Props) {
         mode: 'create',
       })
       await loadStrategies()
-      setActiveTab(result.source)
+      setActiveTab(result.source === 'ai' ? 'ai' : 'custom')
       setImportMsg(`已导入到${result.source === 'ai' ? 'AI' : '自定义'}策略: ${result.strategy_id}`)
     } catch (e: any) {
       setImportError(String(e?.message ?? '导入失败'))
@@ -138,7 +140,7 @@ export function StrategyPoolDialog({ pool, onConfirm, onClose }: Props) {
         animate={{ opacity: 1 }}
         exit={{ opacity: 0 }}
         className="fixed inset-0 z-50 flex items-center justify-center bg-black/50"
-        onClick={e => { if (e.target === e.currentTarget) onClose() }}
+        {...backdrop}
       >
         <motion.div
           initial={{ opacity: 0, scale: 0.95, y: 10 }}
diff --git a/frontend/src/components/screener/StrategySettingsDialog.tsx b/frontend/src/components/screener/StrategySettingsDialog.tsx
index f21db46..0a01321 100644
--- a/frontend/src/components/screener/StrategySettingsDialog.tsx
+++ b/frontend/src/components/screener/StrategySettingsDialog.tsx
@@ -1,7 +1,7 @@
 import { useState, useEffect, useCallback } from 'react'
 import { motion, AnimatePresence } from 'framer-motion'
-import { X, Settings2, RotateCcw, Save, ChevronDown, Filter, Star, TrendingUp, Sparkles, Download } from 'lucide-react'
-import { api, type StrategyDetail, type StrategyParamDef } from '@/lib/api'
+import { X, Settings2, RotateCcw, Save, ChevronDown, Filter, Star, TrendingUp, Sparkles, Download, Layers, Plus, Trash2 } from 'lucide-react'
+import { api, type StrategyDetail, type StrategyParamDef, type CompositeChildInfo } from '@/lib/api'
 import { BUILTIN_COLUMNS } from '@/lib/watchlist-columns'
 import { color } from '@/lib/colors'
 import { SignalPicker } from './SignalPicker'
@@ -216,6 +216,11 @@ export function StrategySettingsDialog({ strategyId, onClose, onSaved, onAiModif
   const [exitSignals, setExitSignals] = useState<string[]>([])
   const [displayLimit, setDisplayLimit] = useState<number | null>(null)
   const [basicFilterEnabled, setBasicFilterEnabled] = useState(true)
+  // 叠加策略: 子策略列表与权重(composite 专属, 编辑权重后随 override 保存)
+  const [compositeChildren, setCompositeChildren] = useState<CompositeChildInfo[]>([])
+  // 可选子策略列表 + 添加面板开关(composite 设置用)
+  const [allStrategies, setAllStrategies] = useState<{ id: string; name: string; source?: string }[]>([])
+  const [showAddChild, setShowAddChild] = useState(false)
   const [editingScoring, setEditingScoring] = useState(false)
   const [deleting, setDeleting] = useState(false)
   const [showDeleteConfirm, setShowDeleteConfirm] = useState(false)
@@ -247,11 +252,32 @@ export function StrategySettingsDialog({ strategyId, onClose, onSaved, onAiModif
         setExitSignals(d.exit_signals ?? [])
         setDisplayLimit(d.display_limit ?? null)
         setBasicFilterEnabled(d.basic_filter?.enabled !== false)
+        setCompositeChildren(d.composite_children ?? [])
+        // composite 策略: 加载全部可选子策略(排除自身和其他 composite)供添加
+        if (d.source === 'composite') {
+          api.screenerStrategies().then(data => {
+            setAllStrategies((data.presets ?? []).filter(s => s.id !== strategyId && s.source !== 'composite'))
+          }).catch(() => setAllStrategies([]))
+        }
       })
       .catch(() => setDetail(null))
       .finally(() => setLoading(false))
   }, [strategyId])
 
+  // 叠加策略: 权重归一(总和→1.0)
+  const compositeTotal = compositeChildren.reduce((s, c) => s + (c.weight || 0), 0)
+  const normalizeCompositeWeights = () => {
+    if (compositeTotal <= 0) return
+    setCompositeChildren(prev => prev.map(c => ({ ...c, weight: Math.round((c.weight / compositeTotal) * 1000) / 1000 })))
+  }
+  const removeCompositeChild = (id: string) => {
+    setCompositeChildren(prev => prev.filter(c => c.id !== id))
+  }
+  const addCompositeChild = (s: { id: string; name: string; source?: string }) => {
+    setCompositeChildren(prev => [...prev, { id: s.id, name: s.name, source: s.source ?? '', weight: 1.0 }])
+    setShowAddChild(false)
+  }
+
   // 保存
   const handleSave = async () => {
     if (!strategyId) return
@@ -268,6 +294,10 @@ export function StrategySettingsDialog({ strategyId, onClose, onSaved, onAiModif
         entry_signals: entrySignals,
         exit_signals: exitSignals,
         display_limit: displayLimit,
+        // 叠加策略: 子策略权重(composite 专属, 走 override.children 持久化)
+        ...(detail?.source === 'composite'
+          ? { children: compositeChildren.map(c => ({ strategy_id: c.id, weight: c.weight })) }
+          : {}),
       })
       onSaved?.(displayLimit)
       onClose()
@@ -298,6 +328,7 @@ export function StrategySettingsDialog({ strategyId, onClose, onSaved, onAiModif
         setExitSignals(d.exit_signals ?? [])
         setDisplayLimit(d.display_limit ?? null)
         setBasicFilterEnabled(d.basic_filter?.enabled !== false)
+        setCompositeChildren(d.composite_children ?? [])
       } finally {
         setResetting(false)
       }
@@ -347,7 +378,7 @@ export function StrategySettingsDialog({ strategyId, onClose, onSaved, onAiModif
             <div className="flex items-center gap-2.5">
               <Settings2 className="h-4 w-4 text-accent" />
               <span id="strategy-settings-title" className="text-sm font-semibold text-foreground">{detail?.name ?? strategyId}</span>
-              {detail && <span className="text-[10px] px-1.5 py-0.5 rounded bg-elevated text-muted">{{ builtin: '内置', custom: '自定义', ai: 'AI' }[detail.source] ?? detail.source}</span>}
+              {detail && <span className="text-[10px] px-1.5 py-0.5 rounded bg-elevated text-muted">{{ builtin: '内置', custom: '自定义', ai: 'AI', composite: '叠加' }[detail.source] ?? detail.source}</span>}
               <span className="text-[10px] text-muted/40 font-mono">{strategyId}</span>
             </div>
             <div className="flex items-center gap-2">
@@ -394,7 +425,87 @@ export function StrategySettingsDialog({ strategyId, onClose, onSaved, onAiModif
                   </div>
                 </div>
 
-                {/* 三列 */}
+                {/* 叠加策略: 子策略列表 + 权重(替换三列参数, composite 专属) */}
+                {detail.source === 'composite' ? (() => {
+                  const SRC_LABEL: Record<string, string> = { builtin: '内置', custom: '自定义', ai: 'AI' }
+                  const SRC_CLS: Record<string, string> = {
+                    builtin: 'border-accent/25 bg-accent/10 text-accent',
+                    custom: 'border-amber-400/25 bg-amber-400/10 text-amber-400',
+                    ai: 'border-purple-500/25 bg-purple-500/10 text-purple-400',
+                  }
+                  const selectedIds = new Set(compositeChildren.map(c => c.id))
+                  const candidates = allStrategies.filter(s => !selectedIds.has(s.id))
+                  return (
+                  <div className="rounded-xl border border-teal-500/20 bg-teal-500/5 p-4 space-y-3">
+                    <div className="flex items-center gap-2">
+                      <Layers className="h-4 w-4 text-teal-400" />
+                      <span className="text-sm font-medium text-foreground">子策略与权重</span>
+                      <span className="text-[10px] text-muted flex items-center gap-1.5">
+                        共 {compositeChildren.length} 个 · 权重总和 {compositeTotal.toFixed(2)}
+                        {compositeTotal > 0 && Math.abs(compositeTotal - 1) > 0.001 && (
+                          <button onClick={normalizeCompositeWeights} className="text-teal-400 hover:text-teal-300 underline underline-offset-2">归一</button>
+                        )}
+                      </span>
+                      <button onClick={() => setShowAddChild(v => !v)} className="ml-auto inline-flex items-center gap-1 h-6 px-2 rounded-lg border border-teal-500/30 bg-teal-500/10 text-[11px] text-teal-400 hover:bg-teal-500/20">
+                        <Plus className="h-3 w-3" />添加
+                      </button>
+                    </div>
+                    {/* 添加子策略面板 */}
+                    {showAddChild && (
+                      <div className="rounded-lg border border-border bg-base/60 p-2 space-y-1 max-h-48 overflow-y-auto">
+                        {candidates.length === 0 ? (
+                          <div className="text-[11px] text-muted py-2 text-center">无可添加的策略</div>
+                        ) : candidates.map(s => (
+                          <button key={s.id} onClick={() => addCompositeChild(s)} className="flex w-full items-center gap-1.5 rounded px-2 py-1 text-left hover:bg-teal-500/10">
+                            <Plus className="h-3 w-3 shrink-0 text-teal-400" />
+                            <span className="flex-1 truncate text-xs text-foreground">{s.name}</span>
+                            {s.source && (
+                              <span className={`rounded border px-1 text-[8px] ${SRC_CLS[s.source] ?? ''}`}>{SRC_LABEL[s.source] ?? s.source}</span>
+                            )}
+                          </button>
+                        ))}
+                      </div>
+                    )}
+                    {compositeChildren.length === 0 ? (
+                      <div className="text-xs text-muted py-4 text-center">暂无子策略, 点击"添加"选择</div>
+                    ) : (
+                      <div className="space-y-1.5">
+                        {compositeChildren.map((c, i) => (
+                          <div key={c.id} className="flex items-center gap-2 rounded-lg bg-base/60 px-3 py-2">
+                            <span className="text-[10px] text-muted/50 font-mono w-5">{i + 1}</span>
+                            <div className="flex-1 min-w-0">
+                              <div className="flex items-center gap-1.5">
+                                <span className="text-xs font-medium text-foreground truncate">{c.name || c.id}</span>
+                                {c.source && (
+                                  <span className={`rounded border px-1 text-[8px] shrink-0 ${SRC_CLS[c.source] ?? ''}`}>{SRC_LABEL[c.source] ?? c.source}</span>
+                                )}
+                              </div>
+                              <div className="text-[10px] text-muted/50 font-mono">{c.id}</div>
+                            </div>
+                            <div className="flex items-center gap-1 shrink-0">
+                              <input
+                                type="number"
+                                step={0.05}
+                                min={0}
+                                value={c.weight}
+                                onChange={e => setCompositeChildren(prev => prev.map((p, j) => j === i ? { ...p, weight: parseFloat(e.target.value) || 0 } : p))}
+                                className="w-16 h-7 px-1.5 rounded-lg bg-base border border-border/40 text-xs font-mono text-foreground text-center focus:outline-none focus:border-accent/50"
+                              />
+                              <button onClick={() => removeCompositeChild(c.id)} className="text-danger/50 hover:text-danger p-1">
+                                <Trash2 className="h-3 w-3" />
+                              </button>
+                            </div>
+                          </div>
+                        ))}
+                      </div>
+                    )}
+                    <div className="text-[10px] text-muted/60 pt-1 border-t border-border/30">
+                      提示: 权重建议归一为 1.0; 修改后点底部"保存设置"生效。
+                    </div>
+                  </div>
+                  )
+                })()
+                : (
                 <div className="grid grid-cols-3 gap-5 items-start">
                   {/* 列1：选股条件 */}
                     <Section icon={Filter} title="基础参数" accent="text-sky-400">
@@ -557,6 +668,7 @@ export function StrategySettingsDialog({ strategyId, onClose, onSaved, onAiModif
                     )}
                   </div>
                 </div>
+                )}
               </>
             ) : (
               <div className="flex items-center justify-center py-16 text-sm text-muted">加载失败</div>
@@ -570,7 +682,7 @@ export function StrategySettingsDialog({ strategyId, onClose, onSaved, onAiModif
                 className="inline-flex items-center gap-1.5 h-8 px-3 rounded-lg border border-border bg-surface text-xs text-secondary hover:text-danger hover:border-danger/30 transition-colors cursor-pointer disabled:opacity-50">
                 <RotateCcw className="h-3.5 w-3.5" />{resetting ? '重置中…' : '重置默认'}
               </button>
-              {(detail?.source === 'ai' || detail?.source === 'custom') && (
+              {(detail?.source === 'ai' || detail?.source === 'custom' || detail?.source === 'composite') && (
                 <button onClick={() => { setDeleteError(''); setShowDeleteConfirm(true) }}
                   className="text-[10px] text-danger hover:text-danger/80 transition-colors">删除策略</button>
               )}
diff --git a/frontend/src/components/screener/StrategyStoreDialog.tsx b/frontend/src/components/screener/StrategyStoreDialog.tsx
index 8dad99a..dc715dc 100644
--- a/frontend/src/components/screener/StrategyStoreDialog.tsx
+++ b/frontend/src/components/screener/StrategyStoreDialog.tsx
@@ -1,5 +1,6 @@
 import { motion, AnimatePresence } from 'framer-motion'
 import { X, Store, Hammer, Download, Zap } from 'lucide-react'
+import { useDialogBackdrop } from '@/lib/useDialogBackdrop'
 
 interface Props {
   open: boolean
@@ -11,6 +12,7 @@ interface Props {
  * 目标：不定时更新更多策略。功能正在建设中，当前仅占位。
  */
 export function StrategyStoreDialog({ open, onClose }: Props) {
+  const backdrop = useDialogBackdrop(onClose)
   return (
     <AnimatePresence>
       {open && (
@@ -19,7 +21,7 @@ export function StrategyStoreDialog({ open, onClose }: Props) {
           animate={{ opacity: 1 }}
           exit={{ opacity: 0 }}
           className="fixed inset-0 z-50 flex items-center justify-center bg-black/50"
-          onClick={e => { if (e.target === e.currentTarget) onClose() }}
+          {...backdrop}
         >
           <motion.div
             initial={{ opacity: 0, scale: 0.95, y: 10 }}
diff --git a/frontend/src/lib/api.ts b/frontend/src/lib/api.ts
index 9e3a08a..26d6d52 100644
--- a/frontend/src/lib/api.ts
+++ b/frontend/src/lib/api.ts
@@ -426,13 +426,20 @@ export interface StrategyParamDef {
   options?: string[]
 }
 
+export interface CompositeChildInfo {
+  id: string
+  name: string
+  source: string
+  weight: number
+}
+
 export interface StrategyDetail {
   id: string
   name: string
   description: string
   tags: string[]
-  source: 'builtin' | 'custom' | 'ai'
-  execution_backend: 'polars_expr' | 'matrix_native' | 'python_history_legacy'
+  source: 'builtin' | 'custom' | 'ai' | 'composite'
+  execution_backend: 'polars_expr' | 'matrix_native' | 'python_history_legacy' | 'composite'
   asset_types: string[]
   timeframes: string[]
   version: string
@@ -454,6 +461,8 @@ export interface StrategyDetail {
   order_by: string
   descending: boolean
   limit: number
+  // 叠加策略(composite)专属: 子策略列表与合并模式。非 composite 时为 null。
+  composite_children?: CompositeChildInfo[] | null
 }
 
 export interface StrategyBuildResult {
@@ -472,7 +481,7 @@ export type StrategyBuildStreamEvent =
 export interface StrategyCodeSaveResult {
   ok: boolean
   strategy_id: string
-  source: 'ai' | 'custom'
+  source: 'ai' | 'custom' | 'composite'
   path: string
   meta: Record<string, any>
 }
@@ -733,6 +742,9 @@ export interface StrategyBacktestResult {
     score_max: number | null
     max_hold_days: number | null
     source: string
+    execution_backend?: string
+    // 叠加策略回测: 子策略构成与权重归因
+    composite_children?: { id: string; weight: number }[]
   }
   elapsed_ms: number
   error: string | null
@@ -2186,6 +2198,21 @@ export const api = {
       body: JSON.stringify(payload),
     }),
 
+  /** 创建/更新叠加策略(composite): 声明式引用多个子策略 */
+  strategySaveComposite: (payload: {
+    strategy_id: string
+    name: string
+    description?: string
+    children: { strategy_id: string; weight: number }[]
+    merge_mode: 'union' | 'intersect'
+    min_confirm?: number
+    mode: 'create' | 'update'
+  }) =>
+    request<StrategyCodeSaveResult>('/api/strategies/composite/save', {
+      method: 'POST',
+      body: JSON.stringify(payload),
+    }),
+
   /** 保存 AI 生成的策略文件 */
   strategySaveCode: (strategyId: string, code: string, meta?: { name?: string; description?: string }) =>
     request<{ ok: boolean; path: string }>('/api/strategies/ai/save', {
diff --git a/frontend/src/pages/Screener.tsx b/frontend/src/pages/Screener.tsx
index e60c0f3..c195a63 100644
--- a/frontend/src/pages/Screener.tsx
+++ b/frontend/src/pages/Screener.tsx
@@ -22,6 +22,7 @@ import { StrategySettingsDialog } from '@/components/screener/StrategySettingsDi
 import { StrategyPoolDialog } from '@/components/screener/StrategyPoolDialog'
 import { StrategyBuilderDialog } from '@/components/screener/StrategyBuilderDialog'
 import { StrategyStoreDialog } from '@/components/screener/StrategyStoreDialog'
+import { CompositeStrategyDialog } from '@/components/screener/CompositeStrategyDialog'
 import { ListColumnCustomizer } from '@/components/ListColumnCustomizer'
 import { useTableSort } from '@/components/stock-table/useTableSort'
 import { resolveCandleConfig } from '@/lib/list-columns'
@@ -48,6 +49,7 @@ export function Screener() {
   const [showBuilder, setShowBuilder] = useState(false)
   const [builderMode, setBuilderMode] = useState<'create' | 'modify'>('create')
   const [showStore, setShowStore] = useState(false)
+  const [showComposite, setShowComposite] = useState(false)
   const { pool, addToPool, removeFromPool, reorderPool, prune } = useStrategyPool()
   const [cardSize, setCardSize] = useState<CardSize>(loadCardSize)
   // 日k蜡烛图显示开关（仅当 candle 列可见时才有意义；持久化）
@@ -666,6 +668,16 @@ export function Screener() {
                 {visiblePool.length}/{strategyPresets.length}
               </span>
             </button>
+            {/* 创建叠加策略 */}
+            <button
+              onClick={() => setShowComposite(true)}
+              className="inline-flex items-center gap-1.5 h-7 px-3 rounded-btn
+                text-xs font-medium text-teal-400 border border-teal-500/20 bg-teal-500/5
+                hover:bg-teal-500/15 transition-colors cursor-pointer"
+            >
+              <Layers className="h-3.5 w-3.5" />
+              叠加策略
+            </button>
             {/* 创建策略 */}
             <button
               onClick={() => { setBuilderMode('create'); setShowBuilder(true) }}
@@ -995,6 +1007,15 @@ export function Screener() {
         }}
       />
 
+      <CompositeStrategyDialog
+        open={showComposite}
+        onClose={() => setShowComposite(false)}
+        onSavedId={async id => {
+          await qc.fetchQuery({ queryKey: QK.screenerStrategies('all'), queryFn: () => api.screenerStrategies(), staleTime: 0 })
+          addToPool(id)
+        }}
+      />
+
       <StrategyStoreDialog
         open={showStore}
         onClose={() => setShowStore(false)}
diff --git a/frontend/src/pages/backtest/StrategyBacktest.tsx b/frontend/src/pages/backtest/StrategyBacktest.tsx
index 1bfd533..b650520 100644
--- a/frontend/src/pages/backtest/StrategyBacktest.tsx
+++ b/frontend/src/pages/backtest/StrategyBacktest.tsx
@@ -1,7 +1,7 @@
 import { useState, useMemo, useEffect, useRef, type ReactNode } from 'react'
 import { useQuery } from '@tanstack/react-query'
 import { motion, AnimatePresence } from 'framer-motion'
-import { Play, FlaskConical, Clock, Loader2, Square, Search, Plus, X, SlidersHorizontal, BarChart3, Gauge, Zap, ListPlus, HelpCircle, ChevronRight, AlertTriangle } from 'lucide-react'
+import { Play, FlaskConical, Clock, Loader2, Square, Search, Plus, X, SlidersHorizontal, BarChart3, Gauge, Zap, ListPlus, HelpCircle, ChevronRight, AlertTriangle, Layers } from 'lucide-react'
 import {
   api,
   type StrategyBacktestResult,
@@ -149,12 +149,13 @@ function FillRuleHint() {
   )
 }
 
-const SRC_MAP: Record<string, string> = { builtin: '内置', custom: '自定义', ai: 'AI' }
+const SRC_MAP: Record<string, string> = { builtin: '内置', custom: '自定义', ai: 'AI', composite: '叠加' }
 const TRADE_PAGE_SIZE_OPTIONS = [10, 20, 30, 50, 100]
 const BADGE_CLS_MAP: Record<string, string> = {
   builtin: 'bg-secondary/10 text-muted border-border',
   ai: 'bg-purple-500/10 text-purple-400 border-purple-500/30',
   custom: 'bg-amber-400/10 text-amber-400 border-amber-400/30',
+  composite: 'bg-teal-500/10 text-teal-400 border-teal-500/30',
 }
 const FIELD_LABEL: Record<string, string> = {}
 for (const c of BUILTIN_COLUMNS) {
@@ -179,11 +180,12 @@ const BASIC_FILTER_FIELDS = [
   { key: 'turnover_max', label: '最高换手率', unit: '%' },
 ]
 type AdvancedSettingsTab = 'params' | 'filter' | 'entry' | 'exit' | 'scoring' | 'risk' | 'range'
-type StrategyGroup = 'all' | 'custom' | 'ai' | 'builtin'
+type StrategyGroup = 'all' | 'custom' | 'ai' | 'builtin' | 'composite'
 const STRATEGY_GROUPS: { id: StrategyGroup; label: string }[] = [
   { id: 'all', label: '全部' },
   { id: 'custom', label: '自定义' },
   { id: 'ai', label: 'AI' },
+  { id: 'composite', label: '叠加' },
   { id: 'builtin', label: '内置' },
 ]
 const ADVANCED_TABS: { id: AdvancedSettingsTab; label: string }[] = [
@@ -1189,11 +1191,15 @@ export function StrategyBacktest() {
 
   const detail = strategyDetail.data
   const matrixStrategy = detail?.execution_backend === 'matrix_native'
+  const compositeStrategy = detail?.source === 'composite'
   const visibleAdvancedTabs = useMemo(
     () => matrixStrategy
       ? ADVANCED_TABS.filter(tab => tab.id !== 'entry' && tab.id !== 'exit')
-      : ADVANCED_TABS,
-    [matrixStrategy],
+      : compositeStrategy
+        // composite 的 entry/exit/scoring 由子策略决定, composite 层只调合并参数(params Tab)
+        ? ADVANCED_TABS.filter(tab => tab.id !== 'entry' && tab.id !== 'exit' && tab.id !== 'scoring')
+        : ADVANCED_TABS,
+    [matrixStrategy, compositeStrategy],
   )
   const basicFilter = (overrides.basic_filter ?? {}) as Record<string, any>
   const entrySignals = (overrides.entry_signals ?? []) as string[]
@@ -1864,6 +1870,18 @@ export function StrategyBacktest() {
                     </span>
                   )}
                 </div>
+                {/* 叠加策略: 子策略构成归因 */}
+                {result.strategy_info.composite_children && result.strategy_info.composite_children.length > 0 && (
+                  <div className="flex items-center gap-1.5 flex-wrap">
+                    <Layers className="h-3 w-3 text-teal-400 shrink-0" />
+                    <span className="text-[10px] text-muted">叠加 {result.strategy_info.composite_children.length} 策略</span>
+                    {result.strategy_info.composite_children.map(c => (
+                      <span key={c.id} className="text-[9px] px-1.5 py-px rounded border border-teal-500/25 bg-teal-500/10 text-teal-400">
+                        {c.id}<span className="text-teal-400/60 ml-0.5">{(c.weight * 100).toFixed(0)}%</span>
+                      </span>
+                    ))}
+                  </div>
+                )}
                 {result.strategy_info.stop_loss != null && (
                   <span className="text-[10px] text-secondary">止损 {fmtPct(result.strategy_info.stop_loss)}</span>
                 )}