Abstract: With the extension of coal resource mining to complex geological areas in the west, the mining of near vertical thick coal seams faces many safety challenges. Among them, the disasters caused by the lagging collapse of the roof of near vertical thick coal seams seriously threaten the safety production of coal mines. In order to further explore the disaster mechanism of the lagging collapse of the roof of the nearly vertical thick coal seam and propose effective prevention and control measures, the B₃₊₆ coal seam in the southern mining area of Wudong Coal Mine was taken as the research object. The theoretical analysis and on-site monitoring methods were comprehensively used to study the relationship between the lagging collapse distance of the roof and the high-energy manifestation of the nearly vertical thick coal seam. A mechanical model for the lagging collapse of the roof of the nearly vertical thick coal seam was established, and the stress distribution mechanics analysis of the roof of the nearly vertical thick coal seam was given. The stress concentration factor of the roof was defined, and the stress concentration factor calculation cloud map under different mining heights and roof thicknesses was obtained. Furthermore, targeted methods for preventing and controlling the impact ground pressure of the nearly vertical thick coal seam were proposed. The research results indicate that:Compared with general collapse, the hanging roof structure caused by lagging collapse has a longer hanging roof distance, higher accumulated elastic energy, and irregular frequency and period of occurrence. The high dynamic load generated by its fracture and the superposition of high static stress in the coal seam are the main reasons for the large energy manifestation of nearly vertical thick coal seams; During the horizontal segmented mining process of nearly vertical thick coal seams, there will be no “square effect” on the roof. However, when the horizontal mining distance reaches 1.2 times the mining height, the stress value increases sharply, and its effect is similar to the “square effect”. This is the critical value for the lagging collapse of the roof of nearly vertical thick coal seams; The precursor conditions for the manifestation of high energy in nearly vertical thick coal seams during horizontal segmented mining are “low energy, low frequency, and long lag distance”; The use of advanced pressure relief blasting with alternating deep and shallow holes can effectively prevent and control the manifestation of high energy in the mining of near vertical thick coal seams.