Abstract: Aiming at the on-site technical problems that coal mining of uncovering coal in crosscut under complex geological conditions is prone to cause coal and gas outburst disasters, the disaster-causing mechanism analysis method is adopted to comprehensively expound the geological conditions and gas occurrence characteristics during the excavation of −850 crosscut and their influences on the causes of coal and gas outburst disasters. The numerical simulation method was applied to conduct a three-dimensional evolution analysis of the stress distribution and failure range of the surrounding rock during the coal mining process of uncovering coal in crosscut. The analysis of the disaster-causing mechanism shows that in the −850 crosscut tunneling area, there are soft coal seams in the structure, and factors such as sudden changes in coal seam thickness are prone to cause coal and gas outbursts. The crosscut tunneling passes through geological structure areas such as faults, and the high gas content and high gas pressure are highly likely to cause abnormal gas outburst. The numerical simulation results show that when crosscut is 2 meters close to the sudden change in coal thickness, the internal stress of the roadway roof rock layer increases by 14.7 MPa, and the failure range of the surrounding rock layer reaches the maximum value of 182 m³. Under the influence of coal seam stress, the deformation of the crosscut roof is more severe and gradually expands upwards. At this time, the coal mining area of uncovering coal in crosscut is highly prone to coal and gas outburst disasters under the influence of changes in gas pressure and stress. A systematic analysis was conducted on the disaster-causing mechanism during the tunneling of crosscut, and measures to prevent coal outburst of uncovering coal in crosscut based on the “strong-weak-strong” structure were proposed.