Abstract: In order to study the atomization characteristics of air-water spray in underground coal mine,the electromag- netic flowmeter,air-mass flowmeter and Malvern droplet particle size analyzer were used to make a systematic investi- gation on the nozzle flow characteristics and the spatial distribution law and influence factors of atomized particle size based on the experimental system designed by authors. The study results indicate that the water consumption of nozzle appears exponential growth with the increase of water supply pressure,and the air consumption decreases in the way of exponential. With the increase of air supply pressure,the air consumption of nozzle increases in the way of exponen- tial,and the water consumption appears linearly decrease. The particle size of droplets increases with the distance away from nozzle in axial direction. On the longitudinal section near the nozzle,the particle size of droplets increases from inside to outside,and the particle size presents an asymmetric distribution. On the longitudinal section located in cen- tral spray flow,the particle size of droplets near the central axis increases with the distance away from the axis,and it presents an increase trend along gravity direction in the outer domain of spray flow. In the attenuation zone of the spray flow,the particle size of droplets increases continuously along gravity direction. With the increase of water supply pres- sure,the particle size of droplets increases first and then declines slightly. The particle size of droplets decreases with the increase of air supply pressure,and the amplitude shows a decrease trend.