Rotorcraft unmanned aerial vehicle (UAV) has been applied rapidly in the domestic electric power system. However, when loaded with patrol equipment, the drone's endurance time becomes only 20 minutes, which is limited. Therefore, based on machine vision, this paper proposes a key technology of automatic charging control to build the leapfrog automatic charging system. The system comprises of leapfrog type UAV charging platform, UAV automatic charging platform and ground control system. According to the flight control and intelligent control, with the aid of machine vision and image recognition technology to realize high precision positioning and automatic charging platform of intelligent precision landing, considering the connection of the clamping position and charging interface of UAV charging platform, the UAV battery automatic charging and the automatic takeoff and landing recharge are realized. The experimental results show that the problem of high precision positioning during UAV charging is effectively solved by using the leapfrog charging platform and machine vision image recognition and shutdown technology.