The invention relates to an intelligent early warning system, especially a multiple layered real-time early warning system based on target detection, positioning, class recognition of intelligent video analysis and based on network management. The system comprises five portions: a video collecting unit, a video processing unit, an action recognition module based on a rule, a network management platform and an alarming module. The method comprises: 1, a user appointing an early warning rule for every vidicon on the network management platform, realizing a multiple layered real-time early warning mechanism; 2, in the video processing unit, dividing a video sequence into three paths, wherein a path is used for coding and compressing, a path is used for scene analysis, and a path is used for background modeling, the video processing unit has encoding and compressing functions, can obtain a traget track after video analysis; 3, transmitting the traget track via a network to the action recognition module, and performing action recognition according to the rule defined by the user.