Abstract: According to the present situation of the poor borehole sealing quality and low gas pumping efficiency in coal seam, A new method of borehole sealing W as proposed.This method was based on the borehole sealing technology of exhaust flling with closed hole, the combined feeding technology of high pressure blowing a nd negative pressure pumping was put forward, the efficient transportation of sealing powder was realized, and powder flling in the target section was completed.Ceme nt mortar sealing operation was carried out after that, and drilling sealing was completed step by step.Field application results show that the new borehole sealing meth od had obvious technical advantages compared with the traditional cement mortar sealing method, the gas concentration ( up to 83.2%) and the pure gas extraction cap acity ( 23.8 m3/min) were improved greatly, but also the leakage phenomenon outside the hole was effectively suppressed, and the structural damage of the coal seam was reduced obviously.