diff --git a/fluid/neural_machine_translation/transformer/reader.py b/fluid/neural_machine_translation/transformer/reader.py
index 604d1ddc9f4ef347e320b3fe9ac9672bcc4c9447..caede1f77e82796a4750723d139034baae6b66ca 100644
--- a/fluid/neural_machine_translation/transformer/reader.py
+++ b/fluid/neural_machine_translation/transformer/reader.py
@@ -264,7 +264,8 @@ class DataReader(object):
     def batch_generator(self):
         # global sort or global shuffle
         if self._sort_type == SortType.GLOBAL:
-            infos = sorted(self._sample_infos, key=lambda x: x.max_len)
+            infos = sorted(
+                self._sample_infos, key=lambda x: x.max_len, reverse=True)
         else:
             if self._shuffle:
                 infos = self._sample_infos
@@ -278,7 +279,8 @@ class DataReader(object):
                           self._pool_size] = sorted(
                               infos[i * self._pool_size:(i + 1) *
                                     self._pool_size],
-                              key=lambda x: x.max_len)
+                              key=lambda x: x.max_len,
+                              reverse=True)
 
         # concat batch
         batches = []