Abstract: The Intrusion Detection System is one of the important security guarantees for the network system. Firstly, we review research situation of the intrusion detection system which contains model, concept, development history and classification. And its research situation is analyzed. Finally, the development trend of this field is foreseen, which contains developing intelligent collaboration Intrusion detection system with the cooperation mechanism of allocating roles flexibly, integrating the intrusion detection technology with other security technology, fusing the intrusion detection, computer forensics, and working on the intrusion detection system for application layer and IPv6.

Key words: abnormaly detection, network security, misusedetection,  intrusion detection