In this study, the research object is a residential building with area of 120 m2, which is shown in Fig.1. In order to make an effectively comparative study, air volume of different common ventilation mode including natural ventilation, natural inlet and mechanical exhaust, wall type ventilator with heat exchange, ventilation unit with heat exchange, are set to the same. The air velocity is calculated, according to their vent area. Their temperature boundary conditions also are set to be the same. Details of their boundary conditions as follows, Velocity boundary conditions