Abstract: We adopted CFD discrete phase physical mode to simulate the diffusion of coal dust generated in different cutting coal ways, and measured coal dust concentration for five typical straight lines in the model to draw a universal trial general diffusion law. Coal dust generated in downwind cutting coal way, the diffused speed in horizontal direction was fast, but limited the bottom scope of coal face. The peak concentration of center line appeared in the rear of the stoker 10 m to 15 m. Coal dust generated in upwind cutting coal way, the diffused speed in the vertical direction was fast. The peak concentration of center line appeared in the rear of the stoker 5 m to 10 m and higher than the peak concentration of coal dust generated in downwind cutting coal way. The coal dust concentration of different cutting coal ways reached stable in the rear of the stoker 40 m to 50 m in horizontal direction, and the concentration of coal dust at the bottom was higher than that at the top.