Abstract: Policy based network management enables management system to be extended dynamically. It is gaining more and more research and application. A policy based network management model is first, presented and then a policy server’s architecture and policy based network management framework supporting cooperation are defined. The management framework supports administrator to decompose task into several subtasks and use policies to describe these subtasks, and then delegate these policies to policy servers to interpret and execute them. Policy servers in different domains can transfer messages between each other to cooperatively work in order to accomplish global management task. Administrator can modify these policies dynamically according to requirements of network’s growth.