Aiming at the problem that UAV image matching takes long time,an improved UAV image matching algorithm based on SIFT is proposed.By introducing the FAST corner point detection algorithm,which can quickly judge whether it is a corner point by comparing the gray value of the center pixel and the pixel in a certain field,thus improving the speed of the algorithm.At the same time,in order to make up for the shortcomings of the FAST algorithm in searching on the Gaussian difference pyramid,an algorithm based on Ostu and GA is used to segment the image,the Gaussian pyramid is constructed for the segmented image,and the feature points are searched on the Gaussian pyramid.Experimental results show that compared with the traditional SIFT algorithm,the new algorithm improves the speed and accuracy of UAV image matching.