diff --git a/fluid/DeepASR/data_utils/async_data_reader.py b/fluid/DeepASR/data_utils/async_data_reader.py
index 731c55de71e8d4b7db156f1ae72172c36eb1be7a..0c8d010755cc4a947507aeb6a65343f0d160f2be 100644
--- a/fluid/DeepASR/data_utils/async_data_reader.py
+++ b/fluid/DeepASR/data_utils/async_data_reader.py
@@ -185,6 +185,9 @@ class AsyncDataReader(object):
                                corresponding description file.
         drop_frame_len (int): Samples whose label length above the value will be
                               dropped.(Using '-1' to disable the policy)
+        split_sentence_threshold(int): Sentence whose length larger than
+                                the value will trigger split operation.
+                                (Assign -1 to disable split)
         proc_num (int): Number of processes for processing data.
         sample_buffer_size (int): Buffer size to indicate the maximum samples
                                   cached.
@@ -204,6 +207,7 @@ class AsyncDataReader(object):
                  feature_file_list,
                  label_file_list="",
                  drop_frame_len=512,
+                 split_sentence_threshold=512,
                  proc_num=10,
                  sample_buffer_size=1024,
                  sample_info_buffer_size=1024,
@@ -214,6 +218,7 @@ class AsyncDataReader(object):
         self._feature_file_list = feature_file_list
         self._label_file_list = label_file_list
         self._drop_frame_len = drop_frame_len
+        self._split_sentence_threshold = split_sentence_threshold
         self._shuffle_block_num = shuffle_block_num
         self._block_info_list = None
         self._rng = random.Random(random_seed)
@@ -262,7 +267,8 @@ class AsyncDataReader(object):
                     map(lambda info: info[0], bucket_block_info),
                     map(lambda info: info[1], bucket_block_info),
                     map(lambda info: info[2], bucket_block_info),
-                    map(lambda info: info[3], bucket_block_info)))
+                    map(lambda info: info[3], bucket_block_info),
+                    split_sentence_threshold=self._split_sentence_threshold))
 
     # @TODO make this configurable
     def set_transformers(self, transformers):
diff --git a/fluid/DeepASR/infer_by_ckpt.py b/fluid/DeepASR/infer_by_ckpt.py
index 36681e9a2bed9f7c2af8f35a230b9cb6558aa19e..554dd7223d19494efc684a3b60070c76672736d4 100644
--- a/fluid/DeepASR/infer_by_ckpt.py
+++ b/fluid/DeepASR/infer_by_ckpt.py
@@ -207,8 +207,11 @@ def infer_from_ckpt(args):
     label_t = fluid.LoDTensor()
 
     # infer data reader
-    infer_data_reader = reader.AsyncDataReader(args.infer_feature_lst,
-                                               args.infer_label_lst)
+    infer_data_reader = reader.AsyncDataReader(
+        args.infer_feature_lst,
+        args.infer_label_lst,
+        drop_frame_len=-1,
+        split_sentence_threshold=-1)
     infer_data_reader.set_transformers(ltrans)
     infer_costs, infer_accs = [], []
     total_edit_dist, total_ref_len = 0.0, 0
diff --git a/fluid/DeepASR/train.py b/fluid/DeepASR/train.py
index 8373c0e04f3a4a2ae87d129243b519c0e0622144..6073db0d07a436f40ac78e38ef072dd23b9dbad5 100644
--- a/fluid/DeepASR/train.py
+++ b/fluid/DeepASR/train.py
@@ -187,7 +187,7 @@ def train(args):
             return -1.0, -1.0
         # test data reader
         test_data_reader = reader.AsyncDataReader(args.val_feature_lst,
-                                                  args.val_label_lst)
+                                                  args.val_label_lst, -1)
         test_data_reader.set_transformers(ltrans)
         test_costs, test_accs = [], []
         for batch_id, batch_data in enumerate(