diff --git a/python/paddle/v2/dataset/common.py b/python/paddle/v2/dataset/common.py
index e31e501ce93c5dc20693a8724ee7dd864f9aef55..191d9ecfb127c1851a392bc9ec83734d630d0ac4 100644
--- a/python/paddle/v2/dataset/common.py
+++ b/python/paddle/v2/dataset/common.py
@@ -71,7 +71,7 @@ def download(url, module_name, md5sum):
         if retry < retry_limit:
             retry += 1
         else:
-            raise RuntimeError("Cannot download {0} within retry limit {2}".
+            raise RuntimeError("Cannot download {0} within retry limit {1}".
                                format(url, retry_limit))
         print "Cache file %s not found, downloading %s" % (filename, url)
         r = requests.get(url, stream=True)