Abstract: Based on an in-depth analysis of the security requirements of MANET and limitation of existing works,a protocol named Distributed Secure Group Communication Protocol（DSGCP） is proposed.The protocol avoids single-point-of-failure problem,reduces the influence on the group key generation by mobility of nodes and error prone wireless channels,and is fairly robust.Three important algorithms,i.e.,group session key renewal algorithm,group control key renewal algorithm and group communication co-decryption algorithm,are described,and the protocol packet formats and main procedures are presented. Implements the protocol in actual Ad hoc network,and conduct a series of experiments to test its performance in various aspects.