The invention discloses an automatic extraction method for an electric transmission line part of an unmanned aerial vehicle polling image. The method comprises the steps: reading polling image data, performing zooming processing and performing RGB channel data separation and histogram statistic on a color image, traversing the image, and determining the edge information of the image; performing partitioning processing on the image, extracting the characters of the image blocks, aggregating the similar characters, and obtaining characteristic blocks; combined with the inherent attribute of the electric transmission line part, performing feature analysis on the characteristic blocks, determining the categorical attributes of each characteristic block, and marking the parts on the electric transmission line. The automatic extraction method is capable of screening the image obtained by polling, and reducing the burdening of the artificial screening, and has extensive application prospect in the polling field.