diff --git a/demo/sentiment/dataprovider.py b/demo/sentiment/dataprovider.py
index 00f72cecacb454a0dd1184fa2098be4543007de7..4b7f5d0e504aef3884a04cbed8c16503a4079772 100755
--- a/demo/sentiment/dataprovider.py
+++ b/demo/sentiment/dataprovider.py
@@ -32,4 +32,6 @@ def process(settings, file_name):
             word_slot = [
                 settings.word_dict[w] for w in words if w in settings.word_dict
             ]
+            if not word_slot:
+                continue
             yield word_slot, label
diff --git a/demo/sentiment/predict.py b/demo/sentiment/predict.py
index 8ec490f64691924013200a3d0038d39aa834b038..64c78e0d6b9297e7a321a4f070517593b0bfe332 100755
--- a/demo/sentiment/predict.py
+++ b/demo/sentiment/predict.py
@@ -138,7 +138,11 @@ def main():
 
     batch = []
     for line in sys.stdin:
-        batch.append([predict.get_index(line)])
+        words = predict.get_index(line)
+        if words:
+            batch.append([words])
+        else:
+            print('All the words in [%s] are not in the dictionary.' % line)
         if len(batch) == batch_size:
             predict.batch_predict(batch)
             batch = []