diff --git a/lib/qiniu/rs/exceptions.rb b/lib/qiniu/rs/exceptions.rb
index 50d092b..fa123f9 100755
--- a/lib/qiniu/rs/exceptions.rb
+++ b/lib/qiniu/rs/exceptions.rb
@@ -4,9 +4,6 @@ module Qiniu
   module RS
 
     class Exception < RuntimeError
-      def to_s
-        inspect
-      end
     end
 
     class ResponseError < Exception