Abstract: To solve the problems of low dust suppression efficiency by spraying in coal mine and easy water damage caused by larger spraying water consumption in roadway, based on the theory of gas-liquid two－phase flow, particle size distribution and migration laws are numerically simulated by FLUENT software under different spraying pressure, we obtain the fog droplets concentration and particle size distribution. The simulation results show that spraying pressure influences the distribution range of droplets. The distribution areas of droplets in the roadway gradually decrease if the spraying pressure is too large. The particle size distribution of fog droplets at the same spraying pressure is not even and it appears that the smaller fog droplets are in the middle, while the larger droplets are on the both sides of the cross section. When the spraying pressure is 3 MPa, the distribution of droplets is good for reducing the dust and it has the best effect when the distance is 2.8 m away from the nozzle.