Abstract: In order to solve the problem of gas over limit in raw coal bunker in coal preparation plant, taking Tiedong Coal Preparation Plant as the engineering background, the mathematical model and physical model of the raw coal bunker were established and the internal gas concentration distribution in the raw coal bunker was numerically simulated. The results show that without the help of any ventilation equipment, the gas concentration in the original bunker in winter and summer is higher than the concentration stipulated in the Coal Mine Safety Regulations. By increasing the number of vents in the raw coal bunker and increasing the ventilation facilities outside the bunker, four kinds of gas control schemes for the raw bunker are put forward and numerical simulation is carried out. The comparative analysis results show that the two-in-two-out forced ventilation with inlet wind speed of 0.7 m/s can reduce the gas concentration in all parts of the bunker, it can effectively solve the problem of gas over limit in raw coal bunker of Tiedong Coal Preparation Plant.