diff --git a/python/examples/fit_a_line/test_multilang_client.py b/python/examples/fit_a_line/test_multilang_client.py
index c2c58378e523afb9724bc54a25228598d529dd7a..f85814a4b24693c269c192b23f0f5ab1c7d566a6 100644
--- a/python/examples/fit_a_line/test_multilang_client.py
+++ b/python/examples/fit_a_line/test_multilang_client.py
@@ -14,7 +14,10 @@
 # pylint: disable=doc-string-missing
 
 from paddle_serving_client import MultiLangClient
+import functools
 import sys
+import time
+import threading
 
 client = MultiLangClient()
 client.load_client_config(sys.argv[1])
@@ -26,7 +29,22 @@ test_reader = paddle.batch(
         paddle.dataset.uci_housing.test(), buf_size=500),
     batch_size=1)
 
+complete_task_count = [0]
+lock = threading.Lock()
+
+
+def call_back(call_future, data):
+    fetch_map = call_future.result()
+    print("{} {}".format(fetch_map["price"][0], data[0][1][0]))
+    with lock:
+        complete_task_count[0] += 1
+
+
+task_count = 0
 for data in test_reader():
     future = client.predict(feed={"x": data[0][0]}, fetch=["price"], asyn=True)
-    fetch_map = future.result()
-    print("{} {}".format(fetch_map["price"][0], data[0][1][0]))
+    task_count += 1
+    future.add_done_callback(functools.partial(call_back, data=data))
+
+while complete_task_count[0] != task_count:
+    time.sleep(0.1)
diff --git a/python/paddle_serving_client/__init__.py b/python/paddle_serving_client/__init__.py
index 9e32926732ef1b396473dab2a748f24f63e19e7a..58ae09bc7bb3b4e1239e9eca58e325c981158bff 100644
--- a/python/paddle_serving_client/__init__.py
+++ b/python/paddle_serving_client/__init__.py
@@ -431,7 +431,6 @@ class MultiLangClient(object):
     def _pack_feed_data(self, feed, fetch, is_python):
         req = multi_lang_general_model_service_pb2.Request()
         req.fetch_var_names.extend(fetch)
-        req.feed_var_names.extend(feed.keys())
         req.is_python = is_python
         feed_batch = None
         if isinstance(feed, dict):
@@ -440,6 +439,7 @@ class MultiLangClient(object):
             feed_batch = feed
         else:
             raise Exception("{} not support".format(type(feed)))
+        req.feed_var_names.extend(feed_batch[0].keys())
         init_feed_names = False
         for feed_data in feed_batch:
             inst = multi_lang_general_model_service_pb2.FeedInst()
@@ -516,6 +516,9 @@ class MultiLangClient(object):
 
         return unpack_resp
 
+    def get_feed_names(self):
+        return self.feed_names_
+
     def predict(self,
                 feed,
                 fetch,
@@ -548,3 +551,10 @@ class MultiLangPredictFuture(object):
     def result(self):
         resp = self.call_future_.result()
         return self.callback_func_(resp)
+
+    def add_done_callback(self, fn):
+        def __fn__(call_future):
+            assert call_future == self.call_future_
+            fn(self)
+
+        self.call_future_.add_done_callback(__fn__)