Abstract: To discuss the relationship between the development of thoracic aortic dissection(TVD) and hemodynamics,three-dimensional simulation of blood flow in human DeBakey Ⅲ type of TVD is investigated in normal and hypertension blood pressure using computational fluid dynamics.The pathline distributions on longitudinal section and cross-section of true and false lumens,wall pressure and wall shear stress for the blood flow of the TVD of DeBakey type Ⅲ are obtained in a cardiac cycle.Numerical results show that the hemodynamic behaviors are closely related to the blood pressure,while the blood pressure has slight influence on the shear stress distribution.The blood pressure in true lumen is also larger than that in false lumen in systole,which suggests that the lumen may expand along the origin lumen.