Objective The diffferences of the cardiovasular transverse between sea-level and high altitude residents was analysed, by measuring thoracic great vessels diameter with CT scanning .Methods 100 cases residents of high altitude and 100 cases sea-level residents were scaned by CT in lung, and the cardiovascular and pulmonary arterial diameter were measured .Results In high altitude groupe the average transverse diameter(ATD) of aortic arch was (2.59?0.30)cm but in control groupe, ATD was (2.73?0.40)cm. The ATD of right pulmonary veins in high altitude was (1.00?0.30)cm but that of control was(1.19?0.34)cm. The ATD of left subpulmonary arteries in high altitude groupe was (1.30?0.28)cm and that of control was (1.2?0.43)cm.Conclusion The transverse diameter(TD)of pulmonary arteries was larger than those of the control . The TD of great arteries of systemic circuit and pulmonary veins were larger in sea-level residents than those of residents of high altitude.