Abstract: In order to solve the high dust mass concentration problem of the fully- mechanized coal mining face in coal mine, taking No.2225 fully- mechanized coal mining face of Xingdong Mine as a study object, based on the mathematics model, a fully- mechanized coal mining face was established. The FLUENT software was ap plied to the numerical simulation to analyze the air velocity affected to the dust migration law of the fully- mechanized coal mining face. The study results showed that in a certain air velocity scope, with the air velocity increased, the average dust mass concentration of the fully- mechanized coal mining face would steadily reduced. But t he air velocity too high would also cause a negative influence to the working environment and condition. Therefore, an air velocity of 2 m /s at the air inlet was determin ed as the optimized air velocity and under the condition of working environment not influenced, the dust mass concentration would be minimum.