diff --git a/backend/app/services/ext_pull.py b/backend/app/services/ext_pull.py
index 3126da7..8b4060f 100644
--- a/backend/app/services/ext_pull.py
+++ b/backend/app/services/ext_pull.py
@@ -12,6 +12,7 @@ from typing import Any
 
 import httpx
 
+from app.market_time import cn_now, cn_today
 from app.services.ext_data import (
     ExtConfig,
     ExtConfigStore,
@@ -43,14 +44,19 @@ def outbound_headers(user_headers: dict[str, str] | None = None) -> dict[str, st
 
 
 def _in_time_window(start: str | None, end: str | None) -> bool:
-    """检查当前本地时间是否在每日时间窗口内。
+    """检查当前北京时间是否在每日时间窗口内。
 
     start/end 为 "HH:MM" 格式。两者都为 None 时不限制(返回 True)。
     支持跨午夜窗口(如 22:00-02:00)。
+
+    用北京时间而不是本地时间: 这个窗口是照着 A 股交易时段设的, 而
+    market_time 模块开篇就写明「服务器/容器本地时区不可靠 (python:slim
+    镜像默认 UTC)」。UTC 容器里 9:30-15:00 的窗口实际落在北京 17:30-23:00,
+    每天都在收盘之后。
     """
     if not start or not end:
         return True
-    now = datetime.now().strftime("%H:%M")
+    now = cn_now().strftime("%H:%M")
     if start <= end:
         return start <= now < end
     # 跨午夜: 如 22:00-02:00
@@ -258,7 +264,8 @@ async def fetch_and_ingest(
     Returns:
         (rows_written, date_str)
     """
-    day = target_date or date.today()
+    # 同上: 落盘分区按北京日期, 否则 UTC 容器在北京时间 08:00 之前写的是前一天。
+    day = target_date or cn_today()
     rows = await fetch_rows_for_date(config, day)
     if not rows:
         raise ValueError("提取到的行数为 0")
diff --git a/backend/tests/test_ext_pull_time_window.py b/backend/tests/test_ext_pull_time_window.py
new file mode 100644
index 0000000..a46d23f
--- /dev/null
+++ b/backend/tests/test_ext_pull_time_window.py
@@ -0,0 +1,103 @@
+"""扩展数据定时拉取的时间基准测试 — 窗口与落盘日期都按北京时间。
+
+背景: `app/market_time.py` 开篇写明「服务器/容器本地时区不可靠 (python:slim
+镜像默认 UTC), 交易时段判断、实时行情落盘日期等必须显式使用北京时间, 否则
+Docker 部署时轮询窗口与真实交易时段完全错开」。
+
+拉取窗口正是照着 A 股交易时段设的, 落盘分区正是行情日期, 两处却都用了裸的
+`datetime.now()` / `date.today()`。UTC 容器里 09:30-15:00 的窗口实际落在北京
+17:30-23:00, 每天都在收盘之后; 北京时间 08:00 之前落盘写的是前一天的分区。
+
+判据不依赖跑测试的机器在哪个时区: 固定一个北京时刻, 断言窗口按它判断。
+"""
+from __future__ import annotations
+
+from datetime import date, datetime
+
+import pytest
+
+from app.market_time import CN_TZ
+from app.services import ext_pull
+
+
+@pytest.fixture
+def at_beijing(monkeypatch: pytest.MonkeyPatch):
+    """把北京时间钉在给定时刻。"""
+
+    def freeze(moment: datetime):
+        monkeypatch.setattr(ext_pull, "cn_now", lambda: moment)
+        monkeypatch.setattr(ext_pull, "cn_today", lambda: moment.date())
+
+    return freeze
+
+
+def test_window_follows_beijing_time_not_the_machine_clock(at_beijing) -> None:
+    # 北京 10:00, 正在早盘。
+    at_beijing(datetime(2026, 3, 2, 10, 0, tzinfo=CN_TZ))
+    assert ext_pull._in_time_window("09:30", "15:00") is True
+
+    # 北京 17:30 — UTC 容器上「本地 09:30」正是这个时刻, 修复前会误判为在窗口内。
+    at_beijing(datetime(2026, 3, 2, 17, 30, tzinfo=CN_TZ))
+    assert ext_pull._in_time_window("09:30", "15:00") is False
+
+
+def test_window_across_midnight_still_works(at_beijing) -> None:
+    at_beijing(datetime(2026, 3, 2, 23, 0, tzinfo=CN_TZ))
+    assert ext_pull._in_time_window("22:00", "02:00") is True
+    at_beijing(datetime(2026, 3, 2, 1, 0, tzinfo=CN_TZ))
+    assert ext_pull._in_time_window("22:00", "02:00") is True
+    at_beijing(datetime(2026, 3, 2, 12, 0, tzinfo=CN_TZ))
+    assert ext_pull._in_time_window("22:00", "02:00") is False
+
+
+def test_no_window_configured_is_still_unrestricted(at_beijing) -> None:
+    at_beijing(datetime(2026, 3, 2, 3, 0, tzinfo=CN_TZ))
+    assert ext_pull._in_time_window(None, None) is True
+    assert ext_pull._in_time_window("09:30", None) is True
+    assert ext_pull._in_time_window(None, "15:00") is True
+
+
+async def test_default_landing_date_is_the_beijing_date(at_beijing, monkeypatch) -> None:
+    """不传 target_date 时按北京日期落盘。
+
+    北京 00:30 对应 UTC 前一天 16:30, 裸 date.today() 在 UTC 容器上会把当天的
+    数据写进前一天的分区。
+    """
+    at_beijing(datetime(2026, 3, 2, 0, 30, tzinfo=CN_TZ))
+    seen: dict[str, date] = {}
+
+    async def fake_fetch(config, target_date):
+        seen["fetched"] = target_date
+        return [{"symbol": "000001.SZ", "v": 1}]
+
+    def fake_write(rows, config, data_dir, snapshot_date):
+        seen["written"] = snapshot_date
+        return len(rows)
+
+    monkeypatch.setattr(ext_pull, "fetch_rows_for_date", fake_fetch)
+    monkeypatch.setattr(ext_pull, "rows_to_parquet", fake_write)
+
+    written, day_str = await ext_pull.fetch_and_ingest(object(), "/tmp")
+
+    assert written == 1
+    assert seen["fetched"] == date(2026, 3, 2)
+    assert seen["written"] == date(2026, 3, 2)
+    assert day_str == "2026-03-02"
+
+
+async def test_an_explicit_target_date_still_wins(at_beijing, monkeypatch) -> None:
+    # 历史回补路径不受影响。
+    at_beijing(datetime(2026, 3, 2, 10, 0, tzinfo=CN_TZ))
+    seen: dict[str, date] = {}
+
+    async def fake_fetch(config, target_date):
+        seen["fetched"] = target_date
+        return [{"symbol": "000001.SZ", "v": 1}]
+
+    monkeypatch.setattr(ext_pull, "fetch_rows_for_date", fake_fetch)
+    monkeypatch.setattr(ext_pull, "rows_to_parquet", lambda *a, **k: 1)
+
+    _, day_str = await ext_pull.fetch_and_ingest(object(), "/tmp", date(2026, 1, 5))
+
+    assert seen["fetched"] == date(2026, 1, 5)
+    assert day_str == "2026-01-05"