Based on the topography, geomorphic character, stratigraphic tex-ture,physical and machanic indexes of landslide soil of Nanta landslide inTongchuan city and the hydrogeological condition of landsliding areasinformation, etc., this paper analyses the causes of this landslide and app-raises the stability of landslide in detail. It is considered that this is arepeatedly sliding and large scale landslide, the main causes of its form-ing relates to the rock structure and natural factors. It is relatively sta-ble landslide containing unstable factors.