diff --git a/qlib/strategy/base.py b/qlib/strategy/base.py
index fa21fae5f..7a267b511 100644
--- a/qlib/strategy/base.py
+++ b/qlib/strategy/base.py
@@ -1,6 +1,9 @@
 # Copyright (c) Microsoft Corporation.
 # Licensed under the MIT License.
-from qlib.backtest.exchange import Exchange
+from __future__ import annotations
+from typing import TYPE_CHECKING
+if TYPE_CHECKING:
+    from qlib.backtest.exchange import Exchange
 from qlib.backtest.position import BasePosition
 from typing import List, Tuple, Union