Abstract: Impact air flow is the main cause of producing dust in ore dumping chamber and adjacent tunnel when unloading ore in high ore pass.In this paper, the Dense DPM model is adopted to consider the interaction between gas and solid and the interaction of particles collisions.Euler equations are established for gas phase, Lagrangian methods are established for discrete particle and the numerical calculation are made to figure out the impact air flow when unloading ore in high ore pass and the relationship between it and the various influencing factors.The results show that the impact speed increases but the speed growth rate decreases with the unload ore flow increases, the relationship between maximum impact speed and unload ore flow remains approximately power function, the higher the unloading height, the larger the power exponent, and the range of the experimental power exponent is 0.593~0.732.The impact air flow becomes greater with the increase of unloading height and the maximum air flow is approximately proportional to 1.05th power of the height.The impact air flow becomes smaller with the increases of ore particle size and the maximum is approximately proportional to -0.63th power of the particle size.When several middle segments unloading together, the multiply of impact air flow will be reduced due to the flow interaction produced from these middle segments.