Abstract: In order to analyze the movement laws of overlying strata in suberect and extra-thick coal seam mining, and provide basis for its engineering practice and selection of hydraul ic support, based on the physical simulation experiment of similar materials, the authors built the mechanical model of rock-support interaction characteristics with bulk structure of overlying strata to obtain the calculation formula of working resistances of support.The studies show that the overlying strata will be bulk structure under the conditions of large-scale mining space and repeated mining disturbance, and hydraulic support load is the dead weight of loosen rock mass in the natural equilibrium arch of overlying strata. The hydraulic support resistance is not only cIosely related to the width, roof distance of hydraulic support, and the compressive strength of loosen rock mass, but also to the length of working face, and the hydraulic support resistance increases with the increase of the working face length. The rationality of the theoretical derivation is verified by engineering example, and the research results could provide great significance to the analysis of support resistance and the reasonable selection of support types in suberect and extra-thick coal seam mining.