Satellite communication constitutes an essential part of the modern communication domain. With its extensive application, security issues in satellite communication, such as spoofing attacks, data theft, data tampering, and replay attacks, have become increasingly prominent. As a crucial defense in network security protection, identity authentication can effectively identify the identity of each node in the network, achieve two-way authentication and security key negotiation between satellites and users, and resist illegal attacks. This paper presents a lightweight authentication method for satellite communication based on SM9, the Chinese National Cryptography Standard for Identity-Based Cryptography. This approach takes SM9 as the core and combines the characteristics of the satellite communication system to design a comprehensive set of identity authentication and key agreement methods. The experimental results demonstrate that the proposed method meets the requirements of low latency and high security in the satellite communication environment, providing a strong guarantee for the security of satellite communication.