In view of the increasingly high real-time requirement of target detection， a multi-target detection algorithm based on field programmable gate array was proposed. Firstly， the moving targets were extracted through the frame difference method， and then the target segmentation of images after morphological processing was performed based on the distance threshold. Finally， the moving targets were marked and displayed. The system was based on CMOS camera， FPGA， external DDR3 high-speed large-capacity cache， and realized the functions of video image acquisition， storage， target detection and display. The experimental results showed that the target detection system could effectively detect multiple targets in real time， and could reach 38 fps at a resolution of 1 024×600.