NetFlow is one of the most important network information collection protocol,and its latest version is V9.NetFlow can provide detailed statistic information of network flow on the promise of furthest reducing the influences of the performance of routers and switches.This paper discusses the research and implementation of network information collection based on the NetFlow V9 protocol according to the development of NPMS(Network Performance Manage System),that is,how to parse and store the NerFlow V9 flow.