The present invention discloses a method, system and device for implementing identity identifier and location separation, to solve the technical problem that the change of the host IP address results in the connection interrupt of the terminal in the process of moving. By separating and mapping the identity identifier and location identifier, the present invention eliminates the network limitation because of the IP addresses with dual functions of the identity identifier and location identifier; the terminal host identity identifier and the terminal location identifier are mapped, the IP address is used for route only, and the host identity is denoted by the host identifier. Consequently, when the host address is changed because of moving or multi-homing and so on, the route is changed, the host identifier still keeps unchanged, and the network application and connection are not interrupted. Therefore, the continuity of the session can be implemented, the mobility, the multi-homing, the dynamic reallocation of IP addresses, and the inter-access among the different network area can be implemented effectively.