diff --git a/paddle/gserver/gradientmachines/MultiGradientMachine.cpp b/paddle/gserver/gradientmachines/MultiGradientMachine.cpp
index faadca69abd76e96b31103da8af53eb9e9cddc43..4654d0206413ec198da62af12e294cd5b442e735 100644
--- a/paddle/gserver/gradientmachines/MultiGradientMachine.cpp
+++ b/paddle/gserver/gradientmachines/MultiGradientMachine.cpp
@@ -359,9 +359,7 @@ void MultiGradientMachine::getOutArgs(std::vector<Argument>* outArgs,
     thread->waitOutArgsReady();
   }
 
-  // outArgs_.size() only need to be calculated once.
-  static int size = threads_[threads_.size() - 1]->getOutArgs().size();
-  outArgs_.resize(size);
+  outArgs_.resize(threads_[threads_.size() - 1]->getOutArgs().size());
 
   REGISTER_TIMER("copyOutArgs");
   for (size_t i = 0; i < outArgs_.size(); ++i) {