Abstract: The Guanyinping landslide turned up evident deformation. There were two possible cause factors. One is the first-stage impoundment of Xiangjiaba hydropower station and the other is the rebuilding construction of the the 307 provincial road whose cutting and filling project had just been finished. The real cause triggering the landslide deformation remains to be controversial between the reservoir impoundment and the construction of the rebuilt road. Based on the landslide deformation behaviors and the results of in-situ monitoring, the deformation mechanism of the landslide is discussed specifically in this paper. In order to analyze the stability of the landslide, a 2D model is developed by using the finite element numerical simulation. The factors of safety under various operational conditions are calculated through shear strength reduction method. The result shows the following three points:(1)Construction of the rebuilt road and the rising of reservoir water level are both against the whole stability of the landslide, especially the rising of reservoir water level;(2)After the construction of the rebuilt road and the first-stage impoundment, the landslide is in the critical stable state. Supposing no reinforcement measure is taken, the factor of safety reduces continually under the second-stage impoundment and the normal impoundment;(3)The treatment measure of cutting slope and unloading is presented. The factor of safety can meet the requirements of norms under the second-stage impoundment and the normal impoundment after being controlled. The relevant conclusions and methods proposed can provide the references for the treatment for the similar landslides.