Aiming at the problems of ghosting and distortion in the process of UAV low-altitude aerial image Mosaic, an improved algorithm for UAV low-altitude aerial image Mosaic was proposed. The algorithm firstly through the SIFT features of UAV image image mosaicing, and then based on the SIFT algorithm in unmanned aerial vehicle (UAV) image matching problems that exist in the process, to improve the image matching in the process of feature extraction methods, effectively reduced the number of feature points extraction, and uses the direct average fusion method for low pass filter, get spliced images. The simulation results show that the algorithm can effectively solve the problems of ghost and distortion in the process of UAV image Mosaic, and the algorithm runs fast, which has certain military application value.