The invention provides an unmanned aerial vehicle power supply system, comprising an unmanned aerial vehicle dispatching center, a plurality of high-voltage line electricity taking devices, and unmanned aerial vehicle electricity supplementing platforms. The plurality of high-voltage line electricity taking devices are respectively installed on overhead line poles spaced apart by a predetermined distance, each high-voltage line electricity taking device comprises a high-voltage drain line, a voltage transformer electricity taking module, a first switch, an induction coil electricity taking module, a second switch and an AC/DC converter; each unmanned aerial vehicle electricity supplementing platform comprises a parking apron, a DC/DC converter and a first positioning module are arranged inthe parking apron, a first charging input end of the parking apron is connected with the AC/DC converter, and a power supply output end of the parking apron matches an electricity taking input end ofan unmanned aerial vehicle; and the unmanned aerial vehicle is provided with a second positioning module, the unmanned aerial vehicle and the unmanned aerial vehicle electricity supplementing platform are both in wireless communication connection with the unmanned aerial vehicle dispatching center, and the unmanned aerial vehicle dispatching center controls the unmanned aerial vehicle to take electricity according to relative positions of the unmanned aerial vehicle and a plurality of unmanned aerial vehicle electricity supplementing platforms. The unmanned aerial vehicle power supply systemprovided by the invention solves the problem of insufficient endurance of the unmanned aerial vehicle.