Abstract: In connection with the problem of increasing ventilation resistance and wind overspeed in the later stage of Gucheng coal mine, to achieve the purpose of ventilation resistance and speed reduction by buliding auxiliary Ground Chamber. The detachable Chamber installed in the main tower can not only solve the problem of space shortage in the replacement of the skip but also can meet the requirement of ventilation resistance reduction without delaying production. Through the Specific engineering practice, the ventilation problem is solved, which provides a powerful reference basis for coal mine with similar problems when the ventilation system is reformed.