A landslide, known as Yanguan Landslide, took place in Guizhou Town, Zigui County on October 29, 2017. To obtain the geomorphological information of this landslide, the UAV aerial survey technology was applied and the resolution of the UAV images was 2.4 cm. Based upon the UAV images collected, the digital orthophoto map (DOM), digital elevation model (DEM) and 3-D geomorphological model at the landslide site could be derived. The interpretation of the UAV images indicated that a potentially unstable landslide existed around Yanguan Landslide. On the basis of the DEM of Yanguan Landslide and the properties of the geomaterials in this landslide, a numerical model based upon GeoStudio was built for this landslide, in which the seepage field and the stability of this landslide were studied with SEEP/W and SLOPE/W, respectively. The numerical study suggested Yanguan Landslide was mainly induced by the combined influence of the fluctuation of the reservoir water level and the rainfall. Further, the stability of the identified potentially unstable landslide was studied with numerical modelling, the study indicated that the stability of this potential landslide was mainly influenced by the rainfall and this potential landslide may become unstable under the heavy rainfall.