Abstract: Based on the engineering background of the distortion effect of airflow caused by the installation of insert plate components in the intake duct of the mining counter rotating fan, a corresponding grid structure model of this fan was established using simulation software. Combined with the simulation results of the fan's operating efficiency, the optimal number of grid divisions was determined to be 6.62 × 10⁶. Furthermore, the K-ω turbulence model was adopted to simulate the airflow movement inside the ventilation fan. The results showed that the airflow behind the insert plate would form a pair of opposite vortex zones near the inner wall of the ventilation fan on both sides, and the pair of vortex zones on the lower side along the axial direction gradually decreased until they disappeared, while the pair of vortex zones on the upper side migrated and extended towards the bottom position, forming a new pair of vortex zones; Under distorted intake conditions, the overall turbulence and pulsation of the airflow are intensified, and the airflow streamline exhibits flow separation, uniform distribution, and flow aggregation phenomena at the top, middle, and root of the blade, respectively; The relative airflow angle in the distortion zone decreases, which can easily lead to blade channel blockage and, in severe cases, cause the front stage impeller to rotate and stall; After the airflow in the distortion zone passes through the impeller, the maximum and minimum pressure values at the top of the blade are 4.09 kPa and 3.37 kPa, respectively. The distortion airflow has a significant impact on the top of the blade.