Abstract. With numerous high mountains, deep valleys and turbulent rivers, many hydropower plants have been constructed in the south-west China. Reservoir bank slopes are very common in this area, these slopes are widespread and quite often involved in deformation that can result in serious damage and casualties. In case of the Donglingxin landslide, for an in-depth study of processes that can trigger these events, the deformation characteristics and the failure mechanisms of the slope were performed on a detail scale, based on an intensive monitoring of rainfall events, reservoir level fluctuation and groundwater movement. The deformation of the upper part of slope is mainly induced by rainfall events, reservoir level fluctuation affects the deformation of the lower part of slope. The increase of pore water pressure may result in the failure of slope. The filed investigation suggest that the slope is unstable. Drainages is the only stabilization measure which can be implemented, due to very complex geological and geomorphology condition.