To solve the problem of strong mine pressure in the free roadway under the condition of hard roof in extremely thick coal seam, taking the 4305 working face of Yangcheng Coal Mine of Jinan Mining Group as the engineering background, a joint "blasting pre-splitting-large diameter drilling" pressure relief technology for hard roof in thick coal seam was proposed. Through a combination of theoretical analysis, numerical simulation and on-site monitoring, the evolution laws of surrounding rock displacement and stress under different joint pressure relief technical parameters are studied. The results indicate that based on key stratum theory, the target blasting layers were identified as 15.1 m fine sandstone located 2.0 m above the coal seam and 10.6 m fine sandstone at 37.6 m above the coal seam, with pre-splitting heights of 17.1 m and 48.2 m, respectively. The blasting angles were determined as 83° and 87° on the goaf side, and 38° and 66° on the solid coal side. Using Flac3D to analyze the displacement and stress changes in surrounding rock of roadways under different combined pressure relief technical parameters, the optimal solution was determined as follows: drilling holes of φ250 mm×30m arranged at a spacing of 3m, combined with differentiated blasting angles, resulting in a maximum roof displacement reduction to 3.55 cm and a peak vertical stress controlled below 6 MPa. This approach established a three-dimensional pressure relief system characterized by "deep-shallow synergy and layered fracture." Field comparisons between the pressure-relief zone and the non-pressure-relief zone showed that the combined pressure relief technology significantly reduced the convergence of the roof and floor, and two sides of the roadway. The combined pressure relief technology effectively enhanced the stability of the surrounding rock in the gob-side entry, providing a theoretical basis and engineering application support for the prevention and control of rock pressure disasters under conditions of extra-thick coal seams and hard roof strata.