Abstract: The sublevel caving method with bottom pillar is adopted in Chengde Copper Mine. With the development of underground mining and the increase of mined-out area,air leakage occurs in mined-out area. Due to the limitation of mining method,the air leakage channel cannot be filled,blocked and communicated with the surface,which has a serious impact on the stability of mine ventilation system. By analyzing the characteristics of air leakage in the goaf of the mine,a three-dimensional physical model of the surface of the goaf is established. based on Fluent software,the flow field law of air leakage velocity in the goaf is numerically simulated. The research shows that under the condition of surface air leakage in goaf,the distribution of flow field in working face and goaf has obvious zoning law in all directions. When the air leakage goaf channel is closer to the working face,the greater the impact on the airflow of the working face is,the airflow in the goaf tends to move to a certain rule to the return airway. When the air leakage velocity is small,the air flow in the goaf of the air leakage channel and the working face is roughly U-shaped,and the closer to the working face,the greater the air flow. According to the above analysis,it is proposed that the air leakage channel is added to the ventilation network by using the air return through the surface goaf,and the air return through the surface goaf is induced at the point where the wind direction is most likely to change. The induced ventilation system is formed,and the dynamic model of the ventilation system is reconstructed. The induced ventilation research is carried out for the ventilation network the air leakage in the goaf,and the air leakage problem in the goaf is better solved. The above studies reflect that taking the goaf as the induced ventilation network of the ventilation circuit and re-optimizing the ventilation network are effective means to solve the problem of air leakage control in goaf.