Abstract: To improve the network environment adaptation ability of intrusion detection, a distributed intrusion detection model based on multi-level immune detector set is presented. The proposed model consists of detection hosts, detection sub-networks and central detection server. Intrusion Detection System (IDS) is deployed in detection hosts. Detection sub-networks have the same features of their superior intrusion detection network. Central detection server provides supports to detect hosts and sub-networks. Through simulating immune cell in biological immune system, immune detectors in detection host learn and evolve. Proposed model utilizes second-level detector set mechanism and cooperates with central detection server operation of vaccines reception and vaccination to decrease the size of detectors and improve the performance of detection.