Abstract: Frequent rockburst events during the extraction of thick coal seams beneath composite hard roofs present significant hazards. Although conventional roof-depressurization blasting can partially alleviate stress concentration, depressurization failure commonly occurs under composite hard-roof conditions, resulting in limited rockburst prevention effectiveness. Taking repeated rockburst occurrences on a working face with a composite hard roof and a thick coal seam in a specific mine as the engineering context, a combination of theoretical analysis, numerical simulation, and field monitoring was employed to systematically investigate the evolution characteristics of key impact-inducing structures and the failure mechanism of blasting-based depressurization. Based on elucidating the relationship between the fracturing–movement of the composite hard roof and the stress transfer within the coal mass, a structural classification method was established. The roof structures were categorized into four types: Top-mounted pressurization structure, Fracture and pressure relief structure, Shifted pressure regulation structure, and Fracture conducting pressure structure. The results indicate that structural morphology determines the location of stress peaks, the intensity of dynamic disturbances, and the associated rockburst risk. When the blasting angle lies between the overhanging angle and the contact angle of the roof strata, roof movement forms a fracture-induced pressure-relief structure. Although this configuration reduces part of the stress, the area near the gob-side entry remains a high-stress zone, and dynamic loads generated by instability of lower key blocks are prone to superimpose on the coal mass, causing depressurization failure. Comparative analysis between theoretical calculation and UDEC simulations shows that adjusting the blasting angle toward the overhanging angle transforms the roof movement into a displacement-regulated pressure-adjustment structure, significantly lowering the stress peak and shifting it away from the entry, while ensuring sufficient collapse of lower key blocks to effectively attenuate dynamic disturbances. Accordingly, a structural-regulation technique for rockburst prevention was proposed. By optimizing the angle of high-level blasting holes toward the overhanging line - without modifying the layout of low-level holes - the roof structure is guided upward and a more reasonable stress transfer is achieved. Field implementation markedly reduced high-energy roof vibration events, prevented long-distance roof suspension, and ensured safe extraction in subsequent working faces.