diff --git a/python/paddle/dataset/common.py b/python/paddle/dataset/common.py
index 424c121e82eccf5319295ac9a718592ce4fccd61..89b9eb7f48a74d3ec18da1bcd23f98e6b67e440d 100644
--- a/python/paddle/dataset/common.py
+++ b/python/paddle/dataset/common.py
@@ -95,7 +95,7 @@ def download(url, module_name, md5sum, save_name=None):
                 total_length = int(total_length)
                 for data in r.iter_content(chunk_size=4096):
 		    if six.PY2:
-			data = six.b(data)
+                        data = six.b(data)
                     dl += len(data)
                     f.write(data)
                     done = int(50 * dl / total_length)