Abstract: In recent years,unmanned aerial vehicle(UAV)remote sensing technology has been widely applied in the investigation of complex geological conditions. However,current UAV photogrammetry methods still face limitations in accurately reconstructing the surface features of high-steep slopes and extracting discontinuity set information,particularly in constructing three-dimensional geological models involving multiple discontinuity sets. To achieve accurate characterization of discontinuity sets and to construct three-dimensional geological models of high-risk rock masses,this study selected a high-risk rock mass in Baoxing County,Ya'an City,Sichuan Province,as the research object. Based on high-precision optical images acquired through nap-of-the-object photogrammetry and intelligent flight planning,the Structure-from-Motion method was used to generate high-precision point cloud data of the geological structure. The Hough transform algorithm was applied to extract point cloud normal vectors,and the HSV color wheel was employed to color-code different discontinuity sets,enabling the interpretation of discontinuity set information. A three-dimensional geological model of the high-level hazardous rock mass with multiple discontinuity sets was rapidly constructed using Rhinoceros software and the Grillage plug-in. The 3DEC discrete element software was then used to simulate the potential movement behavior of the hazardous rock mass. By comparing the spatial position and morphological features of simulated collapsed blocks with actual observations,the reliability and applicability of the three-dimensional geological model were validated. This approach provides a reference for three-dimensional geological modeling of high-steep slopes.