The Internet Engineering Task Force (IETF) standardized and published the IPv4 protocol in September 1981. After almost 30 years, the remaining IPv4 addresses have been distributed by Internet Assigned Numbers Authority (IANA) in February 2011. Due to the exhaustion of IPv4 addresses, the transition from IPv4 to IPv6 is required definitely. The IPv6 protocol and address will gradually replace IPv4, and they might coexist in the Internet for a long time. In Taiwan, the Government plans to migrate most of websites and Internet services during 2013 to 2016. In order to prevent the IPv6-only users cannot acquire the same information as IPv4 users, some content providers start to evaluate the content consistency of websites. However, these tasks need manpower and waste time. In this paper, we propose an on-line evaluation system for reducing the efforts of content comparison. We utilize the concept of web crawler to detect the website supports dual-stack or not, and evaluate the content consistency automatically. According to the evaluation report, the engineers are able to realize the inconsistent contents of website between IPv4 and IPv6.