diff --git a/fluid/neural_machine_translation/transformer/reader.py b/fluid/neural_machine_translation/transformer/reader.py
index 6170c57f4f212671d4949915a594db1d5ca52b07..9a8e7e365c631bff881040c86aa26fcfb5c9724c 100644
--- a/fluid/neural_machine_translation/transformer/reader.py
+++ b/fluid/neural_machine_translation/transformer/reader.py
@@ -286,15 +286,24 @@ class DataReader(object):
         for info in infos:
             batch = batch_creator.append(info)
             if batch is not None:
-                batches.append([info.i for info in batch])
+                batches.append(batch)
 
         if not self._clip_last_batch and len(batch_creator.batch) != 0:
-            batches.append([info.i for info in batch_creator.batch])
+            batches.append(batch_creator.batch)
 
         if self._shuffle:
             self._random.shuffle(batches)
 
-        for batch_ids in batches:
+        for batch in batches:
+            if self._sort_type == SortType.POOL:
+                batch_ids = [
+                    info.i
+                    for info in sorted(
+                        batch, key=lambda info: info.max_len)
+                ]
+            else:
+                batch_ids = [info.i for info in batch]
+
             if self._only_src:
                 yield [[self._src_seq_ids[idx]] for idx in batch_ids]
             else: