Abstract: With the rapid development of Unmanned Aerial Vehicle(UAV), the UAV has made important breakthroughs in remote control, cruising time and flying quality, which provides a very good prospect for UAV’s application in transmission line maintenance. The UAV’s application in inspecting power transmission lines was discussed in detail in this paper in terms of the model selection principle, the patrol mode, the application features of the unmanned helicopter and the fixed-wing UAVs, the flight type and the relay model of the communication link system.