Abstract: The current Network Management System（NMS） has the following problems：lack of monitor and management of network flow；lack of value-added service function，such as security，counting and network optimization；not supporting the analysis of high layer network management businesses demanded by network administrators and high-level managers.This paper designs a new network flow analysis system（FlowMonitor） to promote NMS and to solve the deficiencies of the conventional NMS.Focusing on the high layer requirements in network management，FlowMonitor can satisfies users’ demands for analysis of using status，security defense and counting model based on the network flow.