The invention discloses an identification distribution and separate-storage method, an identification replacing transmission method and system, relating to the field of network safety. The identification distribution and separate-storage method comprises the following steps of: dividing a heterogeneous wireless network by function into a user domain, an access domain, a service domain and an attribution domain, wherein the service domain comprises at least one access domain, the access domain comprises at least one user domain, and the attribution domain and the service domain are the same network when in local service; and after the successful authentication of a terminal, allocating the attribution domain, the service domain and the access domain with domain identifications domain by domain. Based on the access authentication of the heterogeneous wireless network, the invention provides a mechanism of the identification distribution, the separate storage and the replacing transmission of the identification. In the transmission process of the domain identification in the user domain, the access domain, the service domain and the attribution domain, the real identity and the location information of a terminal can be effectively concealed through the retrieval and the replacement among domains and the dynamic update at different identification mapping servers, thereby enhancing the credible access of the heterogeneous wireless network and the safety protection capacity on mobility problems.