Abstract: Aiming at the images which suffered copy-move tampering, a method of duplicated region detection based on point-matching is proposed. After the feature extraction and matching step, a simple but effective clustering method is presented to classify the matched points. Then the geometric transformation between the classes is estimated by the use of RANSAC algorithm. And the counterpart of the original tampered image is obtained according to the geometric transformation. Finally, a region growing algorithm based on the correlation of pixels is proposed to describe duplicated regions. Simulation results show that the presented clustering method can make up the flaw of traditional one and the proposed duplicated region description algorithm is superior to the mainstream approach both in property and efficiency aspects.