Abstract: This paper researched the integration application effects of gas drainage and water injection in coal seam drilling by using theory analysis,numerical simulation and field test.It concluded that the effective influencing radius of 80 meters depth drilling was 3 meters on the condition of 0.63 MPa of gas pressure,0.069 porosity of coal seam,1.5×10^-3μm² of permeability of coal seam,95 mm of drilling diameter and 13 kPa of extraction pressure.The water injection wetting radius became 6m when injected water into the same drilling 48 hours.As can be seen from the actual effect,dust fall rate were more than56% at different work stages and achieved the aim of "double efficacies of one drilling".