Abstract: In order to understand the influence of a reservoir impoundment on an ancient landslide in the reservoir area, the automatic safety monitoring system with GSM communication and powered by solar energy has been established in the landslide. The monitoring items include the surface and internal deformation, groundwater level, rainfall and reservoir water level. Through the analysis of the safety monitoring data of the landslide, it is believed that the landslide is stable at present. When the water level falls quickly from 149m level, the variation of underground water level obviously lags behind the variation of reservoir water level, which is adverse to the stability of the landslide, so the observation frequency and data analysis should be strengthened.