In order to solve the problems of the low matching rate and the low mosaic efficiency of the traditional image mosaic algorithms, we propose a fast image mosaic algorithm based on area blocking and binary robust invariant scalable keypoints (BRISK). Firstly, we use the frequency domain phase correlation algorithm to find the similar areas between the two images. Secondly, we divide the similar areas into N×N' image blocks evenly and calculate the standard deviation of each image block. Thirdly, selecting two image blocks with large standard deviations in different positions, we coarsely match the feature points by BRISK algorithm. Fourthly, we construct the directed line segments and match the adjacent line segments after obtaining the matching points. Finally, we calculate the projection transformation matrix by the randomly matching point pairs to correct the projection error, and accomplish the image mosaic by weighted fusion and luminance equalization. The experimental results show that the matching correctness of the proposed algorithm is more than 90%, and the mosaic speed is increased by 63.7%.