Abstract: In order to determine the effective drainage radius of borehole accurately and reasonably，the permeability of the coal around the borehole is taken as the main object of study，Comprehensive analysis of the stress field Elasto-plastic and methane seepage field around the borehole ，the dynamic model of coal permeability is established, which considers the effective stress in the mining process and the desorption and contraction of the coal matrix. Based on the basic theory of porous medium seepage, the differential equation of methane seepage in pumping boreholes is established, and taking Shaqu mine No. 4 coal seam as an example, numerical simulation is performed by using Comsol Multiphysics software, the variation law of coal seam permeability and gas pressure is obtained respectively, according to the relevant provisions of extraction standards, and taking the gas pressure 0.74MPa as the critical value, it is determined that the effective drainage radius of the borehole under the simulated condition of 180 days is 1.65m, and the results can provide reference for the actual production.