Xiegou Mine with large production capacity, wide range of mining and the centralized arrangement of the working surface, led to a tight wind volume in the mine, and the ventilation capacity of the main ventilator in the return shaft was near the limit. Through the use of Ventsim 3D ventilation simulation, the real-time simulation of mine ventilation system parameters can be realized, Hardy-Cross iterative method was adopted to calculate ventilation system, combined with the established 3D model, the existed problems of ventilation system were studied to optimize the mine ventilation system in Xiegou Mine.