Abstract: Based on UAV photogrammetry technology, the fine model of mine slope is established, and C++ programming is used to realize the spatial point cloud distribution of rock mass quality index and predict the stability of slope rock mass.Firstly, the 3D point cloud processing software is used to cut, denoise and smooth the model.Secondly, the Rhinoceros surface solid modeling function is used to materialize the geological body surface model.Then, combined with the rhinoceros plug-in griddle, the 3D geological body model mesh is divided.Finally, the *.f3grid file recognizable by FLAC^3D software is exported.Taking a mine slope in Shaoxing Yuecheng district as an example, the model is imported into FLAC^3D calculation.The results show that the maximum displacement of the rock mass affected by the joint is near the "fish fin" shape between the two mines, and the maximum displacement is 3.15 cm.The deformation modulus of the rock mass near the "fish fin" shape is 1 GPa, BQ is 172.2-263.6, which is about the quality of rock mass of grade V-IV.The maximum failure probability of rock mass in this area is 43%, and the stability coefficient is lower than 1.0.The calculation results are consistent with the field investigation conclusion, and the potential threat area of slope is predicted, which provides references for relevant investigation and research.