diff --git a/backend/app/api/screener.py b/backend/app/api/screener.py
index 1650ec2..2302449 100644
--- a/backend/app/api/screener.py
+++ b/backend/app/api/screener.py
@@ -613,7 +613,15 @@ def run_all(request: Request, body: Optional[dict] = None):
     # 解析日期
     raw_date = body.get("as_of")
     if raw_date:
-        as_of = date_type.fromisoformat(str(raw_date)) if isinstance(raw_date, str) else raw_date
+        # 与 /custom、/preset 的 `as_of: date` 同口径: 只收 ISO 日期字符串。
+        # 非字符串原样透传会让 str(as_of) 把 "20260904" 之类写进 strategy_cache.json,
+        # 与其它入口写的 "2026-09-04" 不是同一格式, 后续按 as_of 比对缓存永远失配。
+        if not isinstance(raw_date, str):
+            raise HTTPException(status_code=400, detail="as_of 必须是 YYYY-MM-DD 日期字符串")
+        try:
+            as_of = date_type.fromisoformat(raw_date)
+        except ValueError as e:
+            raise HTTPException(status_code=400, detail=f"日期格式错误: {e}") from e
     else:
         as_of = svc.latest_date()
     if not as_of:
diff --git a/backend/tests/test_screener_run_all_as_of.py b/backend/tests/test_screener_run_all_as_of.py
new file mode 100644
index 0000000..d775d18
--- /dev/null
+++ b/backend/tests/test_screener_run_all_as_of.py
@@ -0,0 +1,103 @@
+"""run_all 的 as_of 入参口径 — 与 /custom、/preset 的 `as_of: date` 契约对齐。
+
+/api/screener/custom 与 /api/screener/preset 走 Pydantic 模型 (`as_of: Optional[date]`),
+非法日期在入口被拦下; run_all 收的是无类型 dict, 同样的入参会漏进业务层。
+本文件锁住三条: 非法字符串被拦、非日期类型被拦、合法日期照常放行。
+"""
+from __future__ import annotations
+
+from dataclasses import dataclass, field
+from datetime import date
+from types import SimpleNamespace
+
+import pytest
+from fastapi import HTTPException
+
+from app.api import screener as screener_api
+from app.services import strategy_cache
+
+AS_OF = "2026-09-04"
+
+
+@dataclass
+class _FakeResult:
+    total: int = 1
+    rows: list = field(default_factory=lambda: [{"symbol": "000001.SZ", "close": 1.0}])
+    as_of: str = AS_OF
+
+
+class _FakeEngine:
+    def has(self, sid: str) -> bool:
+        return sid == "s1"
+
+    def get(self, sid: str):
+        return SimpleNamespace(meta={})
+
+    def run_all(self, context, params_map=None, overrides_map=None, *, strategy_ids=None, parallel=True):
+        return {sid: _FakeResult() for sid in (strategy_ids or [])}
+
+
+class _FakeService:
+    def __init__(self, repo, asset_type="stock"):
+        pass
+
+    def latest_date(self):
+        return date.fromisoformat(AS_OF)
+
+    def build_strategy_context(self, *args, **kwargs):
+        return SimpleNamespace()
+
+
+def _request(tmp_path):
+    repo = SimpleNamespace(store=SimpleNamespace(data_dir=tmp_path))
+    state = SimpleNamespace(repo=repo, strategy_engine=_FakeEngine(), monitor_engine=None)
+    return SimpleNamespace(app=SimpleNamespace(state=state))
+
+
+def _body(as_of):
+    return {
+        "as_of": as_of,
+        "strategy_ids": ["s1"],
+        "asset_type": "stock",
+        "timeframe": "1d",
+    }
+
+
+@pytest.fixture(autouse=True)
+def _fake_service(monkeypatch):
+    monkeypatch.setattr(screener_api, "ScreenerService", _FakeService)
+
+
+@pytest.mark.parametrize("bad", ["not-a-date", "2026-13-01", "2026/09/04"])
+def test_malformed_as_of_string_is_rejected(tmp_path, bad):
+    with pytest.raises(HTTPException) as excinfo:
+        screener_api.run_all(_request(tmp_path), _body(bad))
+    assert excinfo.value.status_code == 400
+
+
+@pytest.mark.parametrize("bad", [20260904, 2026, 1.5, True, ["2026-09-04"]])
+def test_non_string_as_of_is_rejected_and_never_reaches_cache(tmp_path, bad):
+    """JSON 数字等非字符串 as_of 不得被当成日期用作缓存键。
+
+    /preset 的 `as_of: date` 对 int 报 422 (date_from_datetime_inexact),
+    run_all 必须同样拦下, 否则 str(as_of) 会把 "20260904" 之类写进 strategy_cache.json,
+    与其它入口写的 "2026-09-04" 不是同一口径, 缓存按 as_of 比对时永远失配。
+    """
+    with pytest.raises(HTTPException) as excinfo:
+        screener_api.run_all(_request(tmp_path), _body(bad))
+    assert excinfo.value.status_code == 400
+    assert strategy_cache.read_cache(tmp_path) in (None, {}) or not (
+        strategy_cache.read_cache(tmp_path) or {}
+    ).get("results")
+
+
+def test_valid_as_of_still_runs_and_writes_iso_cache(tmp_path):
+    resp = screener_api.run_all(_request(tmp_path), _body(AS_OF))
+    assert resp["as_of"] == AS_OF
+    assert resp["results"]["s1"]["total"] == 1
+    assert (strategy_cache.read_cache(tmp_path) or {}).get("as_of") == AS_OF
+
+
+def test_missing_as_of_falls_back_to_latest_date(tmp_path):
+    resp = screener_api.run_all(_request(tmp_path), _body(None))
+    assert resp["as_of"] == AS_OF