In order to solve the security problems of complex network, the concept and the properties of authentication network are proposed. The authentication system of authentication network is studied in terms of authentication nodes, trusted transmitting, trusted chains transferring and trusted domain extending. The management and the control of authentication network are also researched. Based on these, the authentication-based defense model of complex network is proposed. To satisfy the security demands of complex network, a defense system is built based on the idea which is called 1œcombination of node and network, linkage of inspection, evaluation and prevention1.