The purpose of this study is to improve the stack effect of the staircase and the failure to take into account the opening of the outside door of the staircase, which are the disadvantages of the existing smoke control only vestibule. As a result of the study, the new vestibule and the staircase simultaneous smoke control are equipped with an exhaust flap damper with an effective opening area of about 0.25 m² in the upper part of the staircase, and a ventilator-type air supply fan of about 5 m³/s in the lower part, and take measures to prevent overpressure in the staircase. If you use the new simultaneous smoke control method of the vestibule and staircase, you can achieve the following effects. First, it is possible to open the external entrance door. Second, it can reduce the stack effect. Third, the staircase door closes automatically without fail. And a new method of preventing overpressure was proposed for the vestibule.