The invention belongs to the technical field of unmanned aerial vehicle photogrammetry and power transmission line path selection, and particularly relates to a power transmission line automatic lineselection method based on unmanned aerial vehicle photogrammetry. The method comprises the basic steps of making an image of a planning area, automatically classifying image feature ground objects, automatically searching a power transmission line path, evaluating a pre-selected search scheme result and the like. According to the invention, the unmanned aerial vehicle is used for carrying out real-time flight processing on the planned area and key ground objects thereof; High-resolution image data of related areas are obtained efficiently, the optimization degree of power transmission line path selection and the reasonable effectiveness of paths can be effectively improved through an image processing technology and an automatic power transmission line path searching and selecting algorithm, and optimal selection of power transmission line paths is achieved.