diff --git a/backend/app/api/kline.py b/backend/app/api/kline.py
index 84bea75..c2e7b2e 100644
--- a/backend/app/api/kline.py
+++ b/backend/app/api/kline.py
@@ -736,8 +736,9 @@ def get_minute_batch(request: Request, body: dict):
     _pull("stock", [s for s in full_pull if s not in etf_set], day_start)
     _pull("etf", [s for s in full_pull if s in etf_set], day_start)
     if stale_last:
-        # 增量公共起点 = 最旧尾部 + 1min; 起点更早的重叠由落盘/合并去重吸收
-        inc_start = min(stale_last.values()) + timedelta(minutes=1)
+        # 增量公共起点 = 最旧的最后一根本身: 最后一根是形成中的动态K (分钟内
+        # 收盘/量/额持续变化), 必须重拉并以定版值覆盖; 重叠由 upsert/合并去重吸收
+        inc_start = min(stale_last.values())
         if inc_start < session_end:
             _pull("stock", [s for s in stale_last if s not in etf_set], inc_start)
             _pull("etf", [s for s in stale_last if s in etf_set], inc_start)
diff --git a/backend/tests/test_minute_routing.py b/backend/tests/test_minute_routing.py
index 4c38ee5..2d732b8 100644
--- a/backend/tests/test_minute_routing.py
+++ b/backend/tests/test_minute_routing.py
@@ -363,7 +363,7 @@ def _endpoint_mocks(monkeypatch, local_df: pl.DataFrame, sync_ret: pl.DataFrame
 
 
 def test_minute_batch_tail_stale_pulls_incremental_and_persists(monkeypatch):
-    """尾部落后 (本地连续但根数不足) → 从最后一根+1min 增量拉;
+    """尾部落后 (本地连续但根数不足) → 从最后一根本身增量拉 (动态K重拉覆盖);
     拉取结果落盘, 响应为本地+增量合并去重。"""
     from app.api import kline as kline_api
 
@@ -376,7 +376,7 @@ def test_minute_batch_tail_stale_pulls_incremental_and_persists(monkeypatch):
     result = kline_api.get_minute_batch(req, {"symbols": ["600519.SH"], "date": "2026-01-15"})
 
     assert len(captured) == 1
-    assert captured[0]["start"] == datetime(2026, 1, 15, 9, 34)   # 最后一根 + 1min
+    assert captured[0]["start"] == datetime(2026, 1, 15, 9, 33)   # 从最后一根本身重拉 (动态K覆盖)
     assert captured[0]["asset"] == "stock"
     assert writes and writes[0].height == 2                        # 取到即落盘
     rows = result["data"]["600519.SH"]