Abstract: Aimed at the problem of high dust production at fully mechanized excavating face, Fluent is adopted to make the numerical simulation at fully mechanized excavating face, which uses the long pressure short draw-off local ventilation to prevent the dust, and based on the time scale for vortex dust field diffusion laws. The results show that the wind vortex is the main factor influencing the dust transport, this factor leads to the accumulation of dust under the condition of the eddy current, and then produces "a high concentration of dust producing area"; the study found the main channels of dust diffusion migration, and then find an effective prevention and control of dust area; the early work, the driver of the dust concentration increased rapidly; the sidewalk is the main area of dust accumulation to the tail direction of roadway diffusion migration, and most of dust can not be expelled timely, which brings great safety risk production.