With　the　rapid　growth　of　Internet-scale,　IPv4　address　space　will　run　out　this　year.　Therefore,　the　construction　of　IPv6　network　will　accelerate.　The　length　of　IP　addresses　bits　from　32　bits　to　128　bits　in　the　IPv6　Protocol,　so　it　has　a　vast　address　space.　Since　the　transitional　period　from　IPv4　to　IPv6　requires　a　fairly　long　process,　during　this　period,　we　must　ensure　that　Pv4　and　IPv6　can　exchange　date.　In　this　paper,　we　use　the　AT90RM9200　processor　design　a　flexible,　low-cost　IPv4\IPv6　protocol　converter,　which　support　the　SIP　protocol,　IPv4　and　IPv6　networks　can　communicate　with　each　other,　furthermore,　the　IPv4　network　data　can　be　achieved　through　the　IPv6　network.　©　2011　IEEE.