Abstract: In order to investigate the crack development process influenced by mining damage in the roof strata of coal seam,optimize the drilling hole positions of ground gas pumping,researchers put roof crossing hole in six different angles in Chengzhuang coal mine 4216 return air vice lane,monitored the CMM distribution in the moving process of different face of overlying strata by hole sealing drainage.By analyzing and comparing the drainage data of different drilling holes,drilling holes final positions of ground gas pumping were optimized.