Abstract: The effective radius of drilling gas drainage is directly related to coal mine safety production, gas control inputs, rational use of resources and so on. By using the seepage-heat similar analysis module of ANSYS numerical simulation, it studied the drainage radius and laws of three kinds of permeability environment in Xinfeng Coal Mine, and it found out that drilling drainage was different in three-dimensional space in the range of effective drainage, which was not almost the same. It was negative index relationship between coal seam gas pressure and drainage time. The increase of coal seam permeability coefficient could exponentially shorten the limit drainage time and enlarge effective drainage radius. It was the most important to improve the coal seam permeability coefficient in the process of gas control and use in coal mines, which could not only eliminate outburst, but also enlarge effective drainage radius, and shorten drainage time, thus achieved multiple purposes.