Abstract: Dangerous rock mass refers to the rock mass that is cut by the structural plane and fails under certain inducing factors. As one of the common natural geological disasters, it seriously affects the safety of human life and property in mountainous areas. The exploration, stability evaluation and risk evaluation of dangerous rock mass are difficult problems in the research of geological disaster prevention. Affected by human engineering activities, there are many dangerous rock masses in Baimagou, Xindian Town, Mingshan County. Based on the analysis and Research on the distribution and development characteristics of collapse dangerous rock mass in baimagou, this paper preliminarily summarizes the formation, distribution law and disaster mechanism of dangerous rock mass in Guankou formation (K₂g) of Upper Cretaceous system, and carries out numerical simulation calculation for four collapse dangerous rock bodies in this area by using Rockfall, calculates their movement speed and trajectory, and calculates the rock bounce height and distance, It provides a reference for the stability evaluation and motion trajectory analysis of dangerous rock mass under such engineering geological conditions.