Abstract: The Lenghu Saishiteng Mountain in Qinghai Province has the international first-class optical astronomy observation conditions. It creates a major opportunity for the development of optical astronomy in China and provides a valuable strategic resource for international optical astronomy development. Closely focusing on the engineering and geological site selection problem facing the construction of the Lenghu Saishiteng Mountain Observatory, the engineering and geological site selection evaluation is carried out on the basis of extensive collection of the geological survey results obtained by previous authors, by using a combination of remote sensing images, unmanned aerial photography, numerical simulation and manual ground survey. At this stage, two constructed platforms and two vacant platforms have been identified in Mount Saishiteng. In order to ensure the stability of engineering geological conditions of the constructed platforms and vacant platforms, firstly, manual ground investigation, rock samples and 3D response of slopes of constructed platforms under simulated seismic effects are conducted to determine the stability of platforms. InSAR monitoring and analysis of terrain deformation is then used in the key working area to determine the engineering geological stability of the key working area, and the BP neural network model algorithm is finally used to evaluate the regional engineering and geological stability of the Saishiteng Mountain area. The evaluation results show that although there are faults in the two constructed platforms, the impact on the construction is relatively small; no fault fragmentation zones and fracture structures are found in and around the two vacant platforms. Suggestions are made for the construction of the observatory to minimize the placement of engineering works and important equipment in the filling area, to ensure that the slope of the filling side slope is less than the natural rest angle, and to carry out appropriate engineering treatment for the rubble soil side slopes formed by manual excavation or filling ensure engineering safety and normal use of equipment. At the same time, two recommended platforms of 4300 m and 4050 m are recommended based on the evaluation results of different levels.