Abstract: Structures in metamorphic terrains are very complex and very difficult to study because of polyphase superimposition. So to recognize superposed folds correctly is one of the keys to identify the structures and deformation history in metamorphic terrains. This paper proposes a method of processing images by extracting the practice and checks of this method in the Tonghuashan-Liuhuangshan area in the eastern segment of the South Tianshan Mountains, good results have been achieved.