Aiming at the problem of high dust concentration in the return airflow of working face during the mining of outburst coal seam in a mine in guizhou, the gas drainage boreholes in the plastic zone generated by the advance support pressure in front of the working face were used for water injection process, and the dust concentration at the measuring points under different water injection pressures was tested respectively. The results show that under the same water injection pressure, the dust concentration at the measuring point decreases with the distance from the shearer. When the water injection pressure is 6 MPa, the dust reduction effect and economic cost are the best under the mining conditions of 13163 working face. The average total dust concentration and respirable dust concentration in the airflow at the measuring point decreased by 56.1% and 53.1% respectively.