Abstract: In order to study the effect of hydraulic reaming of through bed hole on gas drainage in Xuehu Mine, the size changes of permeability-increasing circle of drilling were simulated with Flac^3D before and after through bed hole reaming 0.6 ton per meter in coal seam. Gas extraction quantity and effective drainage radius were compared and analyzed during hydraulic reaming 0.6 ton per meter and without hydraulic reaming at bed plate tunnel of 2306 working face in the same extraction time. The result indicates that the permeability-increasing circle of drilling increases by 62.5%; the initial extraction quantity increases by 100%; the total extraction quantity increases by 70% in 75 days; the time that reaching 1.1 m of effective drainage radius of the borehole is shortened by 77.2% after drilling reaming 0.6 ton per meter in coal seam. The drainage efficiency can be improved after hydraulic reaming in Xuehu Mine.