IPv6 is the network layer protocol for the next-generation Internet. As its addresses are 128 bits long,, there has been a more urgent need to realize domain name automatic update supported by DNS (domain name system) to reduce the complexity of network communications. With a view to resolving this problem, the paper makes a study on the schemes of DDNS (dynamic domain name server) at home and abroad, and puts forward a scheme of DDNS based on BIND (Berkeley Internet name domain) , which possesses more satisfactory functions and is easy to develop and convenient for use. It also discusses some key technologies for implementation of the new system, such as the method for automatic detection of IPv6 addresses, the programming of domain name update module, and etc. In the end, the paper makes a summary on this system and proposes the future work.