Based on the limited types of Ultra-small Unmanned Aerial Vehicles (USUAV) payload, a set of camera system is designed by integration of optical, mechanical, and electrical hardware to reach the requirements of good performance and practicability. The performance of the system is analyzed, and the key technology that the commercial digital camera is applied to aircraft equipment is solved. By utilizing system damping technology, the image does not exist blurring. Image motion of camera system during exposure time does not exceed 0.5 pixels, and there is no smear to occur. Through the thermal design of the system, the problem that the camera cannot be started up in the low temperature environment is solved. The camera system is tested in the ultra-small UAV, and clear images are acquired. It is proved that the design is reasonable.