Abstract: In order to solve the problem of lack of theoretical support for the utilization of the hulking features of top-loading pressure relief rock in the deep Buried and medium-thick coal seam, a method for measuring the broken expand coefficient of different measuring points of the top-loading pressure relief rock based on 110 method is proposed. The evolution law of the broken expand coefficient of the top-loading pressure relief rock is excavated, and the hulking features of the the top-loading pressure relief rock are identified. The results show that with the advancement of the working face, the broken expand coefficient of each measuring point becomes smaller, and the stable value is between 1.356 and 1.385. The the top-loading pressure relief rock has the features of gradually decreasing the broken expand coefficient and advancement of the working face. The research results are of great significance for the utilization of the the hulking features of top-loading pressure relief rock in the large-depth and medium-thick coal seam.