Abstract: The technology of mist retarder preventing is used extensively for the prevention of coal self-ignition with the inhibited water mist with nitrogen passes into coal mined-out area.Aiming to the easily blocking of atomizing nozzles，underpowered and limited atomization quantity，a new experimental system of inhibited water mist with nitrogen is built to study atomization parameters through theoretical and experimental analysis.The results show that：①the flow and pressure of gas have linear relationship，which is same to the fluid，and the change trend at different initial setting pressure is similar；② under different initial pressure，the water mist particle size decreases with the increase of gas flow and increase with the increase of gas pressure，water flow and water pressure；③the critical pressure and water gage of atomization device exists when the initial pressure P under certain conditions，the fluid won’t atomised for the water pressure is not enough to overcome the gas pressure of the throat when the water pressure is very small，the pressure value is not the critical pressure when the fog saturation of water mist is 0，the critical pressure of inhibited water mist with nitrogen is higher than the minimum water pressure under normal atomization.The research results will provide a new technical means for mine fire control，and promote the development and application of inhibited water mist with nitrogen in the fire prevention and control technology.