Aiming at the tracking problem of ground moving targets for multi -rotor UAV, in consideration of tracking loss of the target due to the changes of external factors, using the image information of ground target collected by the vision camera as the input of the system, this paper adopted the improved algorithm based on color feature extraction combined with TLD target tracking to ensure that the target can be tracked accurately and stably, and the displacement information can be also obtained. By the design of the internal and external ring cascade PID controller of the position, it then took the horizontal displacement difference between the target and the UAV as the input of the controller, and the motor output was controlled by the position attitude con- troller to realize the position change of UAV, ensuring that the target was always located near the center of the airborne camera field of vision, which realized the autonomous tracking of the UAV for target. Finally, the exper- imental results show that the system can track the target accurately and stably.