diff --git a/data/aishell/aishell.py b/data/aishell/aishell.py
index 17786b5d..d3340fc6 100644
--- a/data/aishell/aishell.py
+++ b/data/aishell/aishell.py
@@ -52,6 +52,7 @@ def create_manifest(data_dir, manifest_path_prefix):
 
     data_types = ['train', 'dev', 'test']
     for type in data_types:
+        del json_lines[:]
         audio_dir = os.path.join(data_dir, 'wav', type)
         for subfolder, _, filelist in sorted(os.walk(audio_dir)):
             for fname in filelist: