diff --git a/demo/sequence-labeling/predict.py b/demo/sequence-labeling/predict.py
index 6465eb0c2f2871ff2996cf2a7d651b67bbb2551b..28044cd5a2e2c02dc757bdc17753cfdfc4d6fd27 100644
--- a/demo/sequence-labeling/predict.py
+++ b/demo/sequence-labeling/predict.py
@@ -107,12 +107,8 @@ if __name__ == '__main__':
 
             labels = np_labels.reshape([-1]).astype(np.int32).tolist()
             label_str = ""
-            count = 0
-            for label_val in labels:
-                label_str += inv_label_map[label_val]
-                count += 1
-                if count == np_lens:
-                    break
+            for i in range(1, np_lens-1):
+                label_str += inv_label_map[labels[i]]
 
             print("%s\tpredict=%s" % (test_examples[index], label_str))
 
diff --git a/paddlehub/reader/nlp_reader.py b/paddlehub/reader/nlp_reader.py
index 1751d4329d03b092197a8d380f540d6625f0a435..75f79e6caa9c02bec630e9d5617d48c32d53a6b5 100644
--- a/paddlehub/reader/nlp_reader.py
+++ b/paddlehub/reader/nlp_reader.py
@@ -302,8 +302,7 @@ class SequenceLabelReader(BaseReader):
         return return_list
 
     def _reseg_token_label(self, tokens, labels, tokenizer):
-        if len(tokens) != len(labels):
-            raise ValueError("The length of tokens must be same with labels")
+        assert len(tokens) == len(labels)
         ret_tokens = []
         ret_labels = []
         for token, label in zip(tokens, labels):
@@ -319,8 +318,7 @@ class SequenceLabelReader(BaseReader):
                 sub_label = "I-" + label[2:]
             ret_labels.extend([sub_label] * (len(sub_token) - 1))
 
-        if len(ret_tokens) != len(labels):
-            raise ValueError("The length of ret_tokens can't match with labels")
+        assert len(ret_tokens) == len(ret_labels)
         return ret_tokens, ret_labels
 
     def _convert_example_to_record(self, example, max_seq_length, tokenizer):