With the vigorous development of highway and railway construction in China, the super-shallow burial of tunnel portals, gullies and valleys in mountain tunnels seriously threatens the safety of tunnel construction and operation period. Taking a super-shallow mountain tunnel as an analysis object, the deformation of surrounding rock of super-shallow mountain tunnel under excavation condition is analyzed by means of numerical simulation and field monitoring. The analysis results show that when the buried depth of tunnel is less than 2 times the diameter of tunnel, the displacement of vault roof is larger after excavation of shallower tunnel; the deformation of surrounding rock after excavation of super-shallow tunnel can be divided into three stages, i.e., the stage of rapid increase of deformation, the stage of slow deformation and the stage of stable deformation; among them, the deformation of surrounding rock in the first stage is the largest, which is the key step in the process of tunnel excavation. Paragraph. Finally, through comparative analysis, it is found that the actual monitoring data and simulation results are basically consistent, and the cumulative deformation value of simulation results is slightly larger than the actual monitoring results, which is because the monitoring process is later than the excavation process. Therefore, it is very important for tunnel safety to grasp the deformation law of surrounding rock in the process of excavation of super-shallow tunnel and formulate scientific and reasonable excavation support measures. The research of this paper is based on engineering examples, and its research results have guiding significance for similar projects.