Abstract: Few sharing methods of delegating information are used in current group proxy signature schemes. A new secure group proxy signature scheme based on sub-secret evolution is proposed in this paper, which is based on CDHP and bilinear pairings. In this scheme, double sub-secret of delegating information is constructed by secret sharing method and cellular automata theory so that sharing secrets can be evolved with the number of proxy signatures. And the correctness, the security and the efficiency of the scheme are analyzed. The scheme is more efficient without trust center, and is proved to have the existential group proxy signature unforgeability under the provable security model of group proxy signature and to be able to can trace proxies abusing proxy signature. Compared with other group proxy signature schemes, this scheme is more secure.