Abstract: Coal seam gas drainage is the most fundamental and most effective measure to solve the problem of coal mine gas.In order to find the reasonable drilling drainage parameters,the fluent fluid dynamics simulation software is applied to analyze drill drainage radius and drainage volume under the different drainage negative pressure,borehole diameter,drainage time and sealing depth.The influence laws of various factors on coal seam gas drainage effect were obtained.Combined with the measured data of Tianchi 401 working face,the 15th coal seam gas drilling drainage parameters of the mine was obtained.