<p>In order to study the mechanism of rockbursts during the mining of steeply inclined ultra-thick coal seam, this paper analyzes the characteristics of rockbursts in the mining process of a middle slicing working face, based on the Dongxia Coal Mine. Based on the seismic source location and moment tensor inversion theory, it is determined that the rockburst mainly occurs in the upper roadway floor area of the middle slicing working face, and the failure type of coal and rock mass is shear failure with stronger disaster. Further, the causes of shear failure in Dongxia Coal Mine are discussed based on the stress distribution characteristics and in situ stress test results. Through discrete element and finite element numerical simulations, the migration of overburden and the evolution of shear stress in the inclined slicing mining of steeply inclined ultra-thick coal seams are investigated. Numerical simulation results show that after mining the upper stage coal seam, the overlying roof rock collapses into the stage coal pillar area, increasing the width of the coal pillar. This promotes the accumulation of elastic energy, which serves as a high static load source for rockbursts in the upper roadway. Meanwhile, strong tectonic stress and the hard floor are the main factors influencing the stress distribution in the floor area, providing a high dynamic load source for floor-type rockbursts in the upper roadway. Finally, the research conclusions are verified according to the microseismic data. The findings in this paper provide both theoretical and practical references for understanding the generation mechanism and preventing rockbursts under similar conditions.</p>