Problems of severe borehole collapse, difficult hole sealing; low extraction concentration, rapid decay, poor drainage effect, gas drainage borehole easily caused CO existed in eight mine. Through research and application of high stress soft coal seam hole sealing technology, high stress soft coal seam hole sealing standard process was formulated, the back pressure grouting method was put forward, which decreased air leak rate of borehole, increased borehole sealing, improved extraction concentration and maximized the gas extraction.