diff --git a/app/db/adapters/history/download.py b/app/db/adapters/history/download.py
index 163846cbd..e4d0ea2dd 100644
--- a/app/db/adapters/history/download.py
+++ b/app/db/adapters/history/download.py
@@ -287,6 +287,12 @@ class SessionDownloadHistoryRepository:
         )
         return [_project_history(record) for record in records]
 
+    async def async_count(self) -> int:
+        """在请求异步 Session 内统计下载历史总数。"""
+        if not isinstance(self._session, AsyncSession):
+            raise RuntimeError("下载历史异步统计需要 AsyncSession")
+        return await DownloadHistoryOper(self._session).async_count()
+
     def stage_delete_history(self, history_id: int) -> None:
         """在请求同步 Session 内暂存下载历史删除。"""
         if not isinstance(self._session, Session):
diff --git a/tests/test_transactional_download_history.py b/tests/test_transactional_download_history.py
index e1979c6aa..2af55b8ed 100644
--- a/tests/test_transactional_download_history.py
+++ b/tests/test_transactional_download_history.py
@@ -205,3 +205,27 @@ def test_session_repository_obeys_caller_transaction(db) -> None:
         repository.stage_delete_history(history.id)
         session.commit()
     assert _repository().get_by_hash("request-history-hash") is None
+
+
+def test_session_repository_counts_history_in_caller_async_session(db) -> None:
+    """请求级 adapter 在调用方 AsyncSession 内统计总数，与分页读取口径一致。"""
+    repository = _repository()
+    baseline_count = asyncio.run(repository.async_count())
+    history_id = repository.add(_history_write(download_hash="request-async-count-hash"))
+
+    async def exercise() -> tuple[int, list[DownloadHistorySnapshot]]:
+        """在同一请求 AsyncSession 内先统计总数再分页读取。"""
+        async with async_session_scope() as session:
+            session_repository = SessionDownloadHistoryRepository(session)
+            total = await session_repository.async_count()
+            records = await session_repository.async_list_by_page(count=10)
+            return total, records
+
+    total, records = asyncio.run(exercise())
+
+    assert total == baseline_count + 1
+    assert any(record.id == history_id for record in records)
+
+    with SessionFactory() as session:
+        with pytest.raises(RuntimeError):
+            asyncio.run(SessionDownloadHistoryRepository(session).async_count())