Abstract: Pressure relief through coal seam drilling is a common method in coal mine rockburst prevention, with its effectiveness linked to the mechanical properties of coal. To investigate the dynamic characteristics of coal from drill holes with varying rockburst tendencies and their anti-rockburst mechanisms, high strain rate impact tests were conducted on pre-drilled coal samples using a Hopkinson bar. The research findings indicate: Under high strain rate loading, drilling significantly mitigates the coal's propensity for rockburst by reducing the transmitted energy ratio, decreasing the dynamic peak strength, dynamic peak elastic modulus, and energy density of the coal sample. This mitigation effect is stronger for coal with high rockburst susceptibility than for coal with low susceptibility; Boreholes alter the pathways and rates of energy dissipation in highly impact-prone coal samples, transforming their failure mode into the initiation, propagation, and convergence of multiple cracks. This significantly prolongs the energy release duration, thereby markedly reducing the energy release rate; Drilling significantly enhances stress wave reflection capacity and wave-blocking effects within coal bodies. Under dynamic impact loading, the energy reflection ratio for highly impact-prone coal samples increases from 19% to 33%, while the energy transmission ratio decreases from 38% to 20%. For weakly impact-prone samples, the energy reflection ratio rises from 43% to 60%, and the energy transmission ratio drops from 13% to 5%; As the borehole diameter increases, high-impact coal samples develop multiple tear-type primary cracks parallel to the loading direction from a single primary crack, with crack propagation rates significantly faster than in low-impact samples; Weakly impact-prone coal samples exhibited a greater number of cracks, forming shear-type primary cracks at a 45° angle to the loading direction. Discontinuity lines resembling a “W” shape were observed in the horizontal displacement contour map, resulting from multiple cracks nucleating simultaneously, propagating in parallel, and ultimately connecting. Regarding both energy dissipation and crack propagation, the pressure-relief drilling mechanism exhibits fundamental differences in preventing coal bursts for high- and low-impact-prone coal bodies: For high-impact coal bodies, the core of pressure relief lies in reducing energy-time density through mode transition, whereas for low-impact coal bodies, it relies on the progressive weakening of structural strength.