Abstract: Ancient landslides in the reservoir region are always of great concern. Therefore, it is important to assess the threats they pose to the safety of hydraulic projects, which should be accomplished by a comprehensive analysis instead of a simple mechanical calculation. Taking ancient landslide No. VIII in Xiabandi reservoir as an example, the authors analyze and predict compressively its stability after impoundment by employing multiple methods including identification by observed geological phenomenon, analysis of genetic mechanisms and inversion of motion features, engineering analogy, rigid body limiting equilibrium calculation, numerical simulation, etc. This comprehensive method can be used to develop guidelines for assuring the stability of reservoir landslides.