I. Introduction
Nowadays, one of the biggest threats to network security is network intrusion. Network intrusion refers to any behavior that threatens or endangers the availability, confidentiality and integrity of the host or network. It is the foundation of all network destruction. Network intrusion detection as an important means of network intrusion prevention, it can judge the intrusion behavior according to the abnormal data of network or host, and achieve the purpose of identifying intrusion behavior. However, the traditional network intrusion detection methods can only detect the new network intrusion passively afterwards, which can not solve the problems of various network intrusion modes and unknown intrusion detection. Research on more accurate and efficient network intrusion detection method has become an urgent task to solve the problem of network security [1].