The invention discloses an automatic cruising type power line detection unmanned aerial vehicle. The unmanned aerial vehicle comprises a main body. The four corners of the upper surface of the main body are respectively provided with a mounting duct and a power motor is fixedly arranged inside each mounting duct. The output shaft of each power motor is fixedly connected with a fan blade connectingplate. The automatic cruising type power line detection unmanned aerial vehicle can carry out temperature detection and electromagnetic detection on a power line. The detection is more accurate. Problems, which cannot be observed by naked eyes, can be detected by the unmanned aerial vehicle. As a result, the detection is more accurate, and no detection blind spot can exist. The unmanned aerial vehicle has the autonomous cruising function, and the extending direction of the power line in a shot picture can be analyzed. Meanwhile, the flight advancing direction of the unmanned aerial vehicle can be adjusted in the self-adaptive mode.