The mine ventilation system, as a critical subsystem within underground mining operations, requires precise control of air volume to achieve optimization of the ventilation system. Local resistance is one of the key factors affecting air volume. To investigate the local flow field characteristics of louvered air windows and the relationship between the blade opening angle and the local resistance coefficient, numerical simulation of Computational Fluid Dynamics (CFD) was used, and combined with field measurements, a three-dimensional simulation study was carried out at different wind speeds and different blade angles to gain a deeper understanding of the performance and optimization potentials of the air windows. The following conclusions were drawn: when the blades are opened at 45°, the high-speed flow field is gradually formed at the inlet of the wind window, and with the increase of the wind speed at the inlet, the peak wind speed and the flow field area of the flow field are increased; when the blade angle is increased from 60°to 90°, the local resistance at the wind window is reduced, and the distribution characteristics of the flow field at the back are changed; the static pressure energy and the kinetic energy are converted into each other during the process of the wind flow passing through the wind window, the vortex formed in the pressurized and decelerated region and the back wind side of the wind door are also changed; the vortex formed at the backwind side of the wind window is also changed. The vortex region formed on the back wind surface becomes the key factor affecting the local resistance and energy loss in the flow field behind the shutter. In addition, the relationship between the local drag coefficient of the windshield and the opening angle of the blades is analyzed by nonlinear fitting, which shows a power function correlation.