The growth process of trees rooting on unstable slopes are unavoidably affected by landslides. The common evidences are trees with curving trunks in case of surviving on slopes. These bent trees are of great implication of existences of old landslide events. In this study it investigated the features of bending trees on the old landslide remains, and proposed a method to restore the forming process of an old landslide event based on growth characteristics of trees on slopes. The pattern of slope deformation as opposed to the bending characteristics of trees during a period of time is analyzed, and then the research on the landslide zoning was carried out according to the bending characteristics of trees located in areas. The method was applied to explore Erguxi Landslide, Lixian County, Sichuan Province. The result can disclose the sliding state of each area of the landslide and deformation state to date. The history of the landslide was rebuilt and the time of the last sliding event was determined by calculating.