Abstract: Supersonic speed airflow can shear liquid film into uniform aerial fog of small particle size in dust suppression by spraying, we use commercial CFD software Fluent to simulate the effect of intake air pressure p_in on gas flow field of new supersonic speed gas atomization nozzle, and the change law of pressure and speed on the axis line of the nozzle under the action of shock wave. Studies show that with the increase of pin, the flow field of shock wave continues to move outward, and get acceleration characteristic curve of internal nozzle; when p_in is 5 atm (1 atm=101 325 Pa), the number of shock is the maximum in the nozzle with severe pulsating indicators on the axis; according to the pressure curve, we know that the airflow jets out as compression wave and causes the nozzle damage when p_in is in the minizone around 10 atm and 25 atm respectively.