Abstract: To address the stability issue of the rock slopes on the open-pit mining site in Xizang， the mining site slopes were divided into three structural face identification areas. Using UAV oblique pho⁃ tography and the SIFT algorithm，a 3D model was constructed. Combined with the independently devel⁃ oped RMV3D software，the high-precision identification of structural faces was achieved，and a complete slope stability evaluation technical system was constructed. The results show that by using the pole isoden⁃ sity map method and cluster analysis to identify the dominant structural faces，Area 1 and Area 3 have mainly nearly upright structural faces（295°∠87°，197°∠85°，accounting for approximately 70%），while Area 2 has two sets of structural faces（249°∠55° and 337°∠76°）. The oblique projection analysis indi⁃ cates that there is a local risk of slope failure in the step slopes，and Areas 2 and 3 may undergo wedge�shaped failure along the combined structural faces. Quantitative calculations show that under the condi⁃ tions of cohesion of 20 kPa and internal friction angle of 28°，the safety factors of Area 2 and Area 3 are 2.131 and 2.852 respectively，meeting the specification requirements. The research provides technical ref⁃ erences for the stability evaluation of slopes in high-altitude complex terrain.

Key words: UAV oblique photogrammetry, rock slope, structural plane identification, slope failure