A unified authentication method for providing different application services in a trunking system, wherein the trunking system is a dedicated wireless communication system directed to specific applications in an industry, which is developed to meet needs of commanding and dispatching by a user within the industry, wherein the trunking system comprises an authorization authentication network of a server and multiple application service network elements of the server to provide the different application services and wherein the authorization authentication network element is an authentication authorization server, AAS, logic network element and the multiple application service network elements associated with the applications comprise a user information server, UIS, logic network element, a session initiation protocol core, SIP core, logic network element, a short data service, SDS, logic network element, comprising: receiving, by one application service network element of the server of the multiple application service network elements of the server, a registration request transmitted by a terminal, wherein the registration request carries a token associated with a unique identity of a user initiating the registration request and the identity of the user, User ID, and the token is assigned by the authorization authentication network element of the server to the user when the user logs onto the terminal; performing, by the one application service network element of the server of the multiple application service network elements of the server, a registration to the terminal according to the User ID, and transmitting the token to the authorization authentication network element of the server; performing, by the authorization authentication network element of the server, a token authorization to the user according to the token; and performing, by the one application service network element of the server of the multiple application service network elements of the server, an application service interaction with the terminal if the token authorization is passed; performing, by each of the other multiple application service network elements of the server, the token authorization with the authorization authentication network element according to the same token to provide respective different application services to the terminal so as to implement a unified authentication authorization of each of the multiple application service network elements of the server. receiving, by one application service network element of the server of the multiple application service network elements of the server, a registration request transmitted by a terminal, wherein the registration request carries a token associated with a unique identity of a user initiating the registration request and the identity of the user, User ID, and the token is assigned by the authorization authentication network element of the server to the user when the user logs onto the terminal; performing, by the one application service network element of the server of the multiple application service network elements of the server, a registration to the terminal according to the User ID, and transmitting the token to the authorization authentication network element of the server; performing, by the authorization authentication network element of the server, a token authorization to the user according to the token; and performing, by the one application service network element of the server of the multiple application service network elements of the server, an application service interaction with the terminal if the token authorization is passed; performing, by each of the other multiple application service network elements of the server, the token authorization with the authorization authentication network element according to the same token to provide respective different application services to the terminal so as to implement a unified authentication authorization of each of the multiple application service network elements of the server.