Abstract: Disclosed is a two-phase access authentication method integrating spatial-temporal features in space-air-ground integrated networks. In the method, an access authentication is divided into two phases: a primary authentication phase and a continued authentication phase. In the primary authentication phase, a user equipment and a satellite are respectively initialized and registered through a ground network control center. In the authentication phase, a fast and secure access is achieved by using a user ID, facial features, and other authentication factors. In the continued authentication phase, data of a user flow and behavior features are acquired, and feature comparison is performed by using historical user data; and a security level and an authentication decision are output.