Abstract: Under the same or similar external conditions, the similarity degree of internal structure and external performance of landslide can be clearly demonstrated by the similarity of movement of landslide monitoring points. Thus, it is of important theoretical value and practical significance to use appropriate similarity evaluation method. In this paper, a method based on motion-angle-difference is proposed to evaluate similarity of movement of landslide monitoring points. The velocity of landslide deformation is converted to angle, and the acceleration of landslide deformation is converted to motion-angle-difference. By comparing the motion-angle-differences, the similarity of different landslide monitoring points could be accurately evaluated. In view of the sufficient data, the three dimensional motion-angle-difference is proposed. In this way, not only the distinguishable responses of each monitoring point to the same external influencing factors are emphasized, but also the scale effect can be effectively eliminated. Through a set of experiments, the applications of this method have generated great results, such as partition evaluation of similarity of different monitoring points on the same landslide, evaluation of similarity of different landslides in the Three Gorges Reservoir Region, and displacement prediction of similar landslide monitoring points.

Key words: motion-angle-difference, landslide, monitoring point, similarity