Abstract: The gas overrunning occured usually in fully mechanized working face and upper corner, which has became one of the important reasons that affected mining normally. In illustrate to the geological features of roof rock and mining conditions in W1305 working face of Sihe Coal Mine, the coal seam mining numerical simulation model was established, and the position of high level long borehole and design scheme was determined through theoretical analysis and numerical simulation, the effect of coal seam mining on the gas drainage with the high level long borehole was analyzed. The application shown that the high level long borehole has obvious advantage: extending over long distances, covering a wide range, and can guarantee the drilling in the coal seam roof fracture zone extending, meanwhile, it can achieve continuous regional gas drainage. The single largest hole gas drainage flow over more than 30 m3/min and the gas concentration decreased significantly at the upper corner and the return airway during the period of working face cutting coal, so it has achieved excellent effect of gas extraction and governance.