The invention discloses an autonomous line patrol method for an electric system based on an unmanned aerial vehicle, and relates to the technical field of electric system patrol. The method takes theunmanned aerial vehicle as a carrying main body, and comprises a line patrol method for the electric system, under high light, by the unmanned aerial vehicle, and a line patrol method for the electricsystem, under dim light or no light, by the unmanned aerial vehicle. The autonomous line patrol method for the electric system based on the unmanned aerial vehicle is characterized in that in a patrol process of the unmanned aerial vehicle, imaging equipment generates an image, the image is remotely transmitted to a control room through an image processor and a communication base station, a supply worker searches a fault point, and the characteristics of high working efficiency, high accuracy rate and great working range are achieved; besides, for the condition with dim light and no light, thermal imaging equipment is carried on the unmanned aerial vehicle, and a temperature of a fault point is relatively prominent to achieve the purpose of continuously performing line patrol work on theelectric system in case of relatively dim light and even no light. The way improves work efficiency of processing an emergency event by a night repair team.