A mobile terminal registration method in a radio network includes: a. A mobile terminal sending a non-access stratum message and identifier information of last registration to a radio access network unit, and the identifier information comprising the Serving CN Node identifier, Serving CN Node pool identifier and Public Land Mobile Network Identifier; b. If the radio access network unit determines that the identifier information is invalid, the radio access network unit allocating a Serving CN Node to the mobile terminal and sending the non-access stratum message to the Serving CN Node; c. After the Serving CN Node receives the non-access stratum message, if determining that a registration request of mobile terminal can be accepted, the Serving CN Node sending a success response message to the mobile terminal, and the message carrying identifier information of current Serving CN Node; d. The mobile terminal saving the new identifier information.