Because the network security management system has the disadvantages of data incompleteness, data recovery difficulty and poor privacy. So, this paper applies the cloud computing method to the network security management system and puts forward a network security management system based on cloud computing. This system can integrate information resources effectively and improve the utilization rate of network resource drastically. It realizes the network security management system based on cloud computing through analyzing and researching the cloud computing and network management features. Practice has proved that the system has made great progress in the aspects of network security management, resource sharing, reducing management costs and flexibility compared with traditional management methods. We can say that the efficient computing power and great storage capacity of cloud computing has been fully reflected by the network security management system, which makes the level of our network security management to get a whole improvement.