diff --git a/backend/app/services/paper_trading_service.py b/backend/app/services/paper_trading_service.py
index 00cc992..81a8944 100644
--- a/backend/app/services/paper_trading_service.py
+++ b/backend/app/services/paper_trading_service.py
@@ -267,10 +267,13 @@ class PaperTradingService:
             db.commit()
             db.refresh(db_order)
 
-            # 同步更新内存缓存
-            order.status = OrderStatus.OPEN
-            order.filled_price = filled_price
-            order.opened_at = db_order.opened_at
+            # 使用 make_transient 将对象从会话中分离，使其成为独立对象
+            from sqlalchemy.orm import make_transient
+            db.expunge(db_order)  # 从会话中移除
+            make_transient(db_order)  # 使对象独立
+
+            # 用独立的对象替换内存缓存中的旧对象
+            self.active_orders[order.order_id] = db_order
 
             logger.info(f"挂单已激活: {order.order_id} | {order.symbol} {order.side.value} @ ${filled_price:,.2f}")
 
@@ -280,7 +283,6 @@ class PaperTradingService:
                 'order_id': order.order_id,
                 'symbol': order.symbol,
                 'side': order.side.value,
-                'entry_price': order.entry_price,
                 'filled_price': filled_price,
                 'quantity': order.quantity,
                 'signal_grade': order.signal_grade.value if order.signal_grade else None,