Abstract: In order to optimize the spray pressure on the extracting coal face ,we select 4 kinds of common atomizing nozzles, and measure the nozzle macro spray parameters and droplet size on four types of nozzles in different spray pressure including atomizing angle, effective range and Water consumption, and get the relationship between nozzle spray pressure and spray characteristics, droplet size .Thus as the basis that concluding the spray pressure should be to 2MPa in the side of Coal winning machine and Comprehensive tunneling machine , the outer spray pressure should be to 4MPa, the spray pressure of fully mechanized sublevel caving working face coal caving, frame shift and transshipment point, the return air lane and the fully mechanized working face reproduced point should be 8Mpa.Field application shows that after the optimization of spray pressure on the mining work face, all the average dedust rate of fully put working face dust reduces the 107.87mg, respirable dust average dedust rate reduces the 39.58mg, all the average dedust rate of fully mechanized working face dust reduce the 85.8mg, and respirable dust average dedust rate reduces the 43.62mg. Effect of that is remarkable.