diff --git a/vnpy/trader/app/ctaStrategy/ctaEngine.py b/vnpy/trader/app/ctaStrategy/ctaEngine.py
index dff400de..a13177c3 100644
--- a/vnpy/trader/app/ctaStrategy/ctaEngine.py
+++ b/vnpy/trader/app/ctaStrategy/ctaEngine.py
@@ -621,8 +621,9 @@ class CtaEngine(object):
         """全部撤单"""
         s = self.strategyOrderDict[name]
         
-        # 遍历集合，全部撤单
-        for orderID in s:
+        # 遍历列表，全部撤单
+        # 这里不能直接遍历集合s，因为撤单时会修改s中的内容，导致出错
+        for orderID in list(s):
             if STOPORDERPREFIX in orderID:
                 self.cancelStopOrder(orderID)
             else:
diff --git a/vnpy/trader/vtEngine.py b/vnpy/trader/vtEngine.py
index d343ae35..37920001 100644
--- a/vnpy/trader/vtEngine.py
+++ b/vnpy/trader/vtEngine.py
@@ -794,7 +794,7 @@ class PositionDetail(object):
             self.longPosFrozen = self.longYdFrozen + self.longTdFrozen
             self.shortPosFrozen = self.shortYdFrozen + self.shortTdFrozen
         
-        self.output()
+        #self.output()
             
     #----------------------------------------------------------------------
     def output(self):