With the rapid development of Internet and information technology, network office, network education, paperless office has become increasingly popular. Computers and network have become the effective and essential tools of schools, families and enterprises. However, with the popularity of Internet behavior in a work or study environment, the problem that students and employees use the computer and network to do something unrelated with study and work become more and more serious, what's more, children may be misled to visit junk websites. The abuse of computers and network is widespread in enterprises as well. Hence, it is important to build an effective network behavior management system to monitor and manage the internal network hosts behavior. We put forward a network behavior management system based on B/S architecture. Our research facets are as follows:: According to the function of the system and architecture, the system is divided into three layers: Client Management UI layer, Sever layer, Data Memory layer. We have integrated a variety of Monitoring and Management technology and Protocol Analysis technology into the system. The paper first introduce the B/S architecture and compare with the C/S architecture, then detail the system construction, design of three modules, the work flow of the system, and the main functions of the network behavior management. At last, we conclude the prospect of the network behavior management system based on B/S architecture with HTML5 .