In order to improve the security and efficiency of threshold group signature in 5G environment, a new scheme was proposed. The core idea was to introduce message token and dynamic identity to improve the freshness of authentication information and increase the difficulty of enemy attacks. At the same time, the number of interactions between the participating parties was simplified, and some computing tasks were migrated to the server to reduce the computing overhead of the member part. After security analysis, the proposed scheme can resist multiple attacks including replay attack. After performance analysis, the proposed scheme can reduce the interaction with the trusted center twice compared with similar schemes, reduce the signature space by 30%, and have shorter execution time, which is suitable for resource-constrained devices under 5G network.