Aim To assess the relationship between hypertension and aortic dissection. Methods The study consisted of three groups: aortic dissection group (n=19), hypertension group (n=42) and control group (n=41). The structure and function of thoracic aorta were evaluated by multiplane transesophageal echocardiography. Results Compared with control subjects, the systolic and diastolic diameter, intima-media thickness(IMT), stiffness of thoracic aorta were increased and the compliance of thoracic aorta were decreased significantly (p<0.05～0.001) in patients with hypertension and aortic dissection. These changes were aggravated with increasing the grade of hypertension. The systolic and diastolic diameters of thoracic aorta were dialated significantly in patients with aortic dissection than that of in patients with hypertension (p<0.01), and the intima-media thickness, compliance and stiffness were not statistically diffferent between two groups(p>0.05). Conclusions The damaged structure and function of thoracic aorta are the pathological foundation of aortic dissection. The hypertension is the initial cause of these pathological changes.