This paper proposes an automatic panoramic images mosaic algorithm, which achieves precise feature filtering and feature matching, as well as the autosorting and autostitching of  the input images. Firstly this algorithm detects the SIFT(Scale Invariant Feature Transform) feature points of the input images, and searches all the initial features of the images to be matched by the Kd tree, after filtering the initial feature points by the Euclidean distance ratio and the Median Filter algorithm, gets the precise feature points with the RANSAC(RANdom SAmple Consensus) algorithm; and calculates the single relation matrix between the images, on the basis of this, completes the image sorting and image registration, then achieves the panoramic images mosaic. The experimental results show that compared to RANSAC with the Euclidean distance ratio, the algorithm can have higher accuracy, better panorama images mosaic and good robustness.