Abstract: In view of defects of false alarm and fail alarm existed in coal mine video monitoring of moving target by artificial methods, a design scheme of sensing system of multi-target motion state based on DM642 was proposed. The system uses DM642 as the control core and monitoring video as input, and adopts multi-threshold segmentation method, inter-frame difference method and edge detection method to realize sensing of multi-target motion state, and the sensing results are sent to the configuration software to display and alarm via Modbus/TCP protocol. The test results show that the system can use video to realize sensing of multi-target motion state well, and can replace large numbers of special sensors of motion state in traditional video monitoring.