Mine fire is a very dangerous underground disaster. In order to better study the situation and influence range of mine fire, this paper uses Ventsim to establish a three-dimensional visual ventilation model of Yushuling coal mine. The fire simulation of coal mining face and central substation is carried out by simulation method to study the change law of CO concentration, visibility and temperature in different places. The results show that the CO concentration and visibility change greatly in the downstream of the fire source point when a fire occurs in the coal face; As for the temperature, the temperature at the fire source varies greatly, and the temperature below the inclined air shaft hardly changes; All of them show a decreasing trend with the increase of the distance from the fire source; In case of fire in central substation, there are great changes in all substances in the roadway before and after the air door is opened and closed; After the air door is closed, the CO concentration drops sharply, the change rate at the end of the fire is reduced, the end time is advanced to half of the original, the temperature change is relatively small, and the visibility remains low for a long time after the damper is closed and the recovery time is late. The research results have important guiding significance for the escape of underground fire.