Abstract: To solve the problem of unorganized diffusion of composite dust source in coal preparation plant, this study established an equal scale full-size geometric model based on Gongwusu Coal Preparation Plant, and numerically simulated the spatial-temporal evolution mechanism of belt dust source and scraper dust source in the coal preparation plant with CFD-DPM, and applied the dust washing machine in the field, and the results show that: the wind flow flows into the coal preparation plant with a speed of 0.52m/s from the belt lane, and then the wind speed gradually Decrease, when flowing through the four windows of the side wall of the coal processing plant, under the influence of the outside air pressure difference, the wind flow rushes into the coal processing plant from the windows rapidly, and the instantaneous speed can reach up to 0.75m/s, forming four high-speed wind flow bands; the dust diffused by the three windows of the belt lane and the dust produced by the scraper machine are gathered to form a multi-area composite source of dust, which is dispersed throughout the workshop, of which the area of centrifugal machine and the area of the workers' operation are especially The average dust concentration is 201 mg/m3, which has seriously exceeded the requirements of the operation regulations; after the application of dust removal air washer, the dust reduction rate of the air washer to the coal plant workshop is more than 90%, which effectively reduces the dust concentration of the key dust-producing points in the coal plant.