In recent years, the autonomous flight of bionic flapping wing aircraft using vision systems has become a widely promising research direction. However, its limited carrying capacity puts forward strict requirements for the type, size and weight of vision sensors. At present, the size and weight of commercial image processing modules are large, and the image information needs to be transmitted back to the ground control system for processing. Therefore, this paper aims to design a lightweight onboard monocular vision system to help the miniature bionic flapping wing aircraft obtain external information and realize intelligent and autonomous flight. Compared with other image processing modules, this system was designed with domestic high-computing power chip K210 as the core, which could complete image processing without the computer side. The size is only 2.2cm×2.3cm, and the weight is only 3g. The internal compatible lightweight network model realizes classification recognition, and information interaction is achieved through the serial port, which can control the flapping wing aircraft to achieve gesture recognition and target tracking.