With the development of the computer technology and network technology, E-Government has become a hotspot that the global information technology industry are concerned about. Through the untiring efforts of more than ten years, the E-government of our country has already been popularized rapidly. The department and area using the E-government are experiencing the convenience of the network. At the same time they are experiencing the puzzlement that negative factors of network bring, such as the virus, hacker, etc. The question of net safety is outstanding day by day. The national security based on net security has been threatened seriously, too. The net security question in the E-government has already become the factor of restraining the E-government from further developing. Therefore it has received the extensive concern. How to establish the system of safe protection, guarantee the network system to run well and protect the information resource of E-government against violate has already become serious social problem that various countries have concerned. To build secure E-Government network system, we must establish integrated information security ensured system. This system include physical security, network security, system security, application security, data security and security administration. At the same time we must adopt all kinds of advanced technology actively, such as FireWall, Intrusion Detection System, Virtual Private Network, Virtual Local Area Network, encrpytion techniques, PKI, and to realize centralized and unitive scheme, watch and administration. But we defend integrated security of E-Government system, not to accumulate all kinds of security product, but to integrate organically and utilize synthetically these technology. The selected title aims at probing into and studying the network security problem in the E-government in terms of macrocosm. Combine the theory and practice together closely. Study the network system structure of the current E-government of our country and the application situation. Expound the network security demand and risk of the E-government in detail and dissect it deeply. Have proposed system frame of the security, countermeasure and model. Refining the essence of the network security of E-government out from the network security and setting up the macroscopic network security theory of E-government are the innovation herein.