Abstract: The geological environment conditions of Beijing mountainous area are complex, and there are a lot of sudden geological hazards, which not only directly threaten the safety of people and fundamental facilities, roads and scenic spots in mountainous areas, but also threaten the planning and construction of cities and towns. It is a very important work to divide the geological disaster prone areas by evaluation of geological hazard susceptibility, so as to guide the urban construction planning and reduce the threat of geological disasters with the evaluation results. Based on the description of the sudden geological hazards development of rock fall, landslide, unstable slope and debris flow in Beijing mountainous area, the article selects six influencing factors, including slope, fluctuation, rock group of engineering geological, geological structure, geomorphic type and precipitation, and adopts the method of integrated information model to analyze the susceptibility of slope hazards including rock fall, landslide, unstable slope and debris flow in Beijing mountainous area. Then according to the principle of "high not low", the results of susceptibility of various hazards were superimposed to divide the susceptibility of sudden geological hazards in mountainous areas, which provides scientific basis for the suitability evaluation of urban construction, the compilation of land spatial planning and the improvement of spatial governance.