diff --git a/python/paddle/fluid/async_executor.py b/python/paddle/fluid/async_executor.py
index e760d58fd22f2be0448ffcad2cf76145f3755e61..2a6a11805e48d209493e1ae579898dc386c3dd92 100644
--- a/python/paddle/fluid/async_executor.py
+++ b/python/paddle/fluid/async_executor.py
@@ -87,6 +87,7 @@ class AsyncExecutor(object):
 
         scope = global_scope()
         self.executor = core.AsyncExecutor(scope, p)
+        self.instance = None
 
     def run(self, program, data_feed, filelist, thread_num, fetch, mode="", debug=False):
         """
@@ -154,6 +155,9 @@ class AsyncExecutor(object):
 
     def download_data(self, afs_path, local_path, fs_default_name, ugi, process_num=12):
         #hadoop_home = "$HADOOP_HOME"
+        if self.instance is None:
+            raise ValueError('instance is None, please run config_distributed_nodes init instance')
+            
         hadoop_home = "~/tools/hadoop-xingtian/hadoop/"
 
         configs = {
@@ -182,15 +186,21 @@ class AsyncExecutor(object):
         pass
 
     def get_instance(self):
+        if self.instance is None:
+            raise ValueError('instance is None, please run config_distributed_nodes init instance')
         return self.instance
 
     def stop_server(self):
+        if self.instance is None:
+            raise ValueError('instance is None, please run config_distributed_nodes init instance')
         self.instance.barrier_all() #worker do all things
         if self.instance.is_first_worker():
             self.executor.stop_server()
         self.instance.barrier_all() #sync
 
     def init_server(self, dist_desc):
+        if self.instance is None:
+            raise ValueError('instance is None, please run config_distributed_nodes init instance')
         self.executor.init_server(dist_desc, self.instance._rankid)
         ip = self.executor.start_server()
         self.instance.set_ip(ip)
@@ -204,6 +214,8 @@ class AsyncExecutor(object):
         self.instance.barrier_all() #sync
 
     def init_worker(self, dist_desc, startup_program):
+        if self.instance is None:
+            raise ValueError('instance is None, please run config_distributed_nodes init instance')
         place = core.CPUPlace()
         executor = Executor(place)
         executor.run(startup_program)
@@ -217,8 +229,12 @@ class AsyncExecutor(object):
         self.instance.barrier_all() #wait init model
        
     def init_model(self):
+        if self.instance is None:
+            raise ValueError('instance is None, please run config_distributed_nodes init instance')
         self.executor.init_model()
 
     def save_model(self, save_path):
+        if self.instance is None:
+            raise ValueError('instance is None, please run config_distributed_nodes init instance')
         self.executor.save_model(save_path)