The invention discloses an unmanned aerial vehicle life detection method based on multi-source information fusion, and the method comprises the steps: S1, enabling an unmanned aerial vehicle to carrya multi-source sensor for the detection and search of a target area, and enabling the multi-source sensor to comprise a radar sensor, a visible light image sensor, and an infrared thermal image sensor; S2, respectively receiving and preprocessing the radar image, the visible light image and the infrared image to obtain a preprocessed radar image, a preprocessed visible light image and a preprocessed infrared image; and S3, carrying out image registration on the preprocessed visible light image and the infrared image, carrying out fusion, carrying out secondary fusion on a fusion result and theradar image, and outputting a target detection result. The method has the advantages of being simple in implementation method, high in interference resistance and environmental adaptability, high indetection efficiency and precision and the like.