The use of natural ventilation of modern building design is becoming increasingly prevalent in low energy buildings throughout the world. However, it is the difficulty in predicting the efficiency of natural ventilation prevents it to be used widely in multi-zone building design, There are two main kinds of methods, network method and CFD method. Both have their own advantage of both CFD and network methods was developed to predict the efficiency of natural ventilation in multi 7000 m2 floor area. The result shows that the net-field method is an effective method to deal with multi-zone buildings, because it takes an acceptable calculation time to get a relative exact result.