Abstract: The gas emission in Hongyan Coal Mine mainly comes from the gas emission in coal seam. In order to improve the gas extraction efficiency and determine the best hole sealing depth, through the analysis and test of “three zones” scope and pre-pumping gas width of roadway, combined with the comparative test of four groups of boreholes in field, we carry out comparison from coal seam hole, through beds hole, hole sealing depth, hole sealing with or without pressure four aspects. The results show that the main factor influencing the gas drainage concentration of the coal seam is the micro-cracks in the coal seam from pressure relief zone and the concentrated stress zone in the coal seam roadway and borehole “three zones”, and hole sealing with pressure of 12 m is the most ideal hole sealing depth.