In the process of building IPv6 transition network, three common methods of transition are used: double-stack technology, tunnel technology and address translation. Considering the condition that none of the above technologies can transverse NAT, this paper advances a new solution based on Client / Server technology. It summarizes the technological challenges and analyzes possible scenarios during the transition from IPv4 to IPv6, and proposes a new protocol based on tunnel technology which needs less equipment and it can greatly facilitate users. The result of the experiment shows it attains superior effect.