Abstract: In order to analyze the effect of air window on the regulation of wind pressure and air volume, based on the equation of pressure energy conservation and the characteristic curve of wind pressure, the expression of the pressure change before and after the air window was deduced. Based on the insufficiency of air supply in the local roadway of Xinji No. 2 Coal Mine, by numerically simulating the presence or absence of air window in roadway, it can be concluded that the addition of air window will not change the total air flow into the coal mine, it will only change the proportion of air flowing into each roadway, it will also increase the airflow pressure of its branch, decrease the air volume of the same wind road, and increase the air volume of the parallel wind road. Combined with engineering practice, taking the renovation of the ventilation system in a coal mine as an example, it was verified that the addition of air window will change the wind pressure at each roadway and the air volume at the entrance, providing a theoretical basis for the adjustment of on-site air window.