The present invention provides a group identity signature based PMIPV6 anonymous access authentication system and a method. The method comprises: accepting by a third-party trusted center applications for registration from mobile nodes, local mobility anchors and mobile access gateways, issuing public and private key pairs for the mobile access gateways in PMIPv6 networks and the local mobility anchors, and as a group owner, issuing group membership certificates for the mobile nodes; implementing initial access authentication on the mobile nodes when the mobile nodes access for the first time the mobile access gateways in the PMIPv6 networks; and when the mobile nodes are switched among the mobile access gateways in the same PMIPv6 network, calculating by the mobile nodes pseudonyms and private keys of the mobile nodes according to anonymous public keys issued by the local mobility anchors and the group membership certificates, and implementing switching authentication in the PMIPv6 network by an identity of the pseudonyms. According to the present invention, an identity-based agent signature solution is applied to the mobile management process of a PMIPv6 protocol, and a public key certificate is canceled by using a group identity signature technology, thus reducing the storage and the authentication of the legality of the public key certificate, achieving the anonymity of mobile nodes, and realizing privacy protection.