In order to improve the matching accuracy of the original RANSAC algorithm,an improved RANSAC algorithm based on the strategy of twice matching is proposed.Of all the sample points,the feature points with excessive matching errors are eliminated at first,so as to reduce iteration times and accelerate the matching process.Then,the reverse matching method is used for second-time matching,so as to ensure the matching accuracy and reliability of the algorithm.The experimental results show that:1) The matching accuracy and speed of the original algorithm are improved;and 2) The improved algorithm has strong robustness and high reliability under the interference of illumination changes and motion blur.