The arrival of the information age has gradually expanded the practical application of computer networks, provided more convenience for people's lives, and promoted the rapid development of Chinese information industry. In this situation, the process of using computer network has gradually produced network security problems, affected the security of the user's personal information. Affected by various illegal attacks will bury a large security risks to popularization and use of computer network, indirectly reduce the efficiency of a variety of information security transmission, restrict the future level of network services. In order to change the current situation of the development of adverse, we need to pay attention to the rational use of network security technology, structure reliability computer network defense mechanism, enhance the safety performance of network. This will maximize to meet the actual needs of users. Based on this, this paper will carry on the systematic elaboration to the security technology in the computer network.