diff --git a/backend/paper_trading.py b/backend/paper_trading.py
index e3cc884..ca41874 100644
--- a/backend/paper_trading.py
+++ b/backend/paper_trading.py
@@ -12,7 +12,7 @@ paper_trading.py — 模拟盘开仓/平仓辅助函数
 from typing import Optional
 
 from db import get_sync_conn
-from signal_engine import PAPER_FEE_RATE  # 复用全局配置
+PAPER_FEE_RATE = 0.0005  # Taker手续费 0.05%（开仓+平仓各一次）
 
 
 def paper_open_trade(