The invention provides an identity authentication system and a method thereof. Embodiments of the invention provide application, installation, and verification processes of a mobile identification card, and enable a mobile apparatus of a user to be a carrier of the mobile identification card. The mobile identification card can be applied to services related to internal identification of enterprises, groups, or government agencies, and achieve smart and mobile identification. The mobile identification card is provided via an over-the-air mechanism. A mobile enterprise identification card service is provided to one or more enterprises by using a gateway. In addition, in combination with advantages of a dynamic graphics coding technology, a geographic location, data encryption with a key, transaction time recording, and other technologies, a graphic code can be generated for identity authentication. Therefore, highly secure identity authentication can be provided by using a dynamic graphic code.