In view of the difficulty of large and difficult control of dust production in 2-208 fully mechanized coal mining face, the control technology of deep hole dynamic pressure water injection was put forward, the mechanism of coal seam water injection was analyzed and the layout of water injection borehole was determined. The results showed that dynamic pressure water injection can wet coal seam in advance and reduce dust production and flying capacity. The average concentration of dust and respirable dust on the working face was decreased to 24.8% and 28.8% respectively after water injection.