Many of the reservoir is surrounded by mountains, and many reservoirs slope are not receiving proper maintenance. The slopes of adjacent to the reservoir is the blind spot of the administration. Landslides in the reservoir had caused the destruction of the structure from wave and overtopping. In addition, this has a severe impact on the stability of the downstream portion. In this study, an infinite slope stability analysis utilizing the on-site investigation and SINMAP be performed for vulnerability analysis of the landslide of adjacent to the reservoir.