The invention discloses a system and a method for managing security of a general network, and mainly overcomes the defects of poor openness and expansibility and weak functional completeness existing in the prior network security management system. The system mainly comprises peripheral equipment, a security agent terminal, a security management center and terminal management equipment, wherein the security management center applies security technology of network access control, intrusion detection, virus detection and vulnerability management to the security agent terminal through an interface component, a data base module and a user interface component; and under the unified management and control, all security technology is mutually complemented and matched to detect and control network behaviors, so that a distributed security protection system structure in which security strategies are under central management and the security detection is separately distributed is formed. The system and the method have the advantages of flexible configuration, easy expansion, good openness, support of the different level management, and suitability for the security management and protection of the computer network in governments, colleges and universities, and large- and medium-sized enterprises.