Disclosed is a method for automatically extracting and locating power lines based on an unmanned aerial vehicle image. The method comprises the steps that an unmanned aerial vehicle is used for double-air-strip flight to obtain an aerial image; the power lines of the aerial image are automatically extracted, and the aerial image is extracted through an LSD linear detection method; rough extraction is carried out through radiation features of the power lines, and background information is eliminated through connectivity; the background information with an LSD detection image removed is united, the remaining background information is eliminated, and meanwhile the detected power lines are connected; three-dimensional data of the power lines of the aerial image are located to carry out epipolar line image extraction, epipolar lines and wires intersect with one another to solve homonymy point coordinates, the forward intersection is carried out, and the three-dimensional data of the power lines are obtained. The efficiency of a three-dimensional line patrol system is improved, more precise three-dimensional coordinates are obtained, and the cost for power line corridor line patrol is lowered.