Although international researches into the hemodynamics of type B aortic dissection are well under way now, the difficulty in harvesting the aortic dissection flap is keeping us away from its changes of mechanical properties during the course of disease. This article reviews the studies on the relationships between the mechanical properties of type B aortic dissection and its development. And the changes of biomechanics of the intimal flap and its effect on the hemodynamics, the wall stress and the timing choosing of the operation are emphasized, in order to help us to predict the clinical disease of patients and study more about the hemodynamics of chronic dissection model of biomaterial in vitro in near future