Abstract: In or der to effectively solve the problem of low gas extraction efficiency when drilling coal seam in coal roa dway construction, the coal rock mass aroun d the coal roa dway is divi de d into "three zones" un der the effect of stress. Consi dering the characteristics of poor gas permeability an d low permeability of coal bo dy deep in the drilling, the mechanical reaming an d cavitation metho d in the hole is a dopte d to carry out the test.The average gas extraction ra dius of the borehole was increase d by 2.4 times, an d the extraction ra dius can reach 3.7m at 300 days.The gas extraction concentration in the 30 d cycle decays from 97.62% at the peak to 60.55%, an d from 51.77% to 23.69% compare d with the normal drilling, which was still in the state of high concentration extraction.In terms of gas extraction purity in dex, the former was 80.04～31.59 m³/d, the latter is 45.7～11.28 m³/d, an d the extraction effect has obvious technical a dvantages.