Method and system for realizing virtual private network

An implementation method and system of a virtual private network (VPN) are provided. The implementation method and system store an appropriative mapping table of the VPN in the mapping plane of the identity and location separating network, determine whether to implement the communication between the VPN end host users in the VPN according to the appropriative mapping table, and thus implement the virtual private network effectively in the identity and location separating network. The method and system meet the user requirement for the VPN, and eliminate the impact of the technical solution of the identity and location separation on the traditional VPN service, and reduce the changes of the existing equipment and software while implementing the VPN.