It is known that, in ancient China, the sitting styles changed from sitting-on-floor to sitting-on-chair. But the time of turning-point of sitting-on-chair has not been ascertained yet. By dividing into 4 stages, namely, "Age of Sitting-on-Floor", "Appearance of Sitting-on-Chair", "Expansion of Sitting-on-Chair" and "Generalization of Sitting-on-Chair", this study tries to clarify the changing process of sitting styles themselves and its reasons. With the change of sitting styles, the floor structure of building also changed. From the point of view of sitting style, this study tries to clarify the relationship between the change of this behavior style and the change of architectural environment.
