In order to overcome the problems that the existing group proxy signature schemes do not have strong unforgeability and can not resist collusion attack by proxy themselves, a group proxy signature scheme of resisting collusion attack based on key matrix was proposed. Based on CDH problem and bilinear pairings，the traditional secret sharing scheme was improved by using rank of matrix，and its correctness, security and efficiency were analyzed. The scheme enhances intrusion-tolerance of system, has strong unforgeability and non-repudiation, and can resist collusion attack. It is a forward-secure group proxy signature scheme.
