Most patients with ascending aortic aneurysms are young or middle-aged and often have enlarged aortic sinuses and annulus. In severe enlargement, the aortic valve leaflets fail to close together during cardiac diastole, presenting with incomplete aortic valve closure. However, the aortic valve leaflets themselves do not have significant pathology. Ascending aortic aneurysm is not a tumor, but an aneurysmal change in a dilated segment of the ascending aorta. The essence of the disease is a lesion in the middle layer of the great vessels, which causes a weakness in the overall wall, and when the blood pressure is high, it causes the weakness to bulge relatively and form an aneurysm. The cause of this disease is unknown, but most of them may be related to congenital connective tissue diseases (such as Marfan syndrome, which has a genetic predisposition), syphilitic arteritis, and aortic sclerosis. Once the diagnosis of ascending aortic aneurysm is clear, surgical treatment should be performed as soon as possible. In cases not associated with aortic valve insufficiency, surgery should also be considered to prevent aneurysm rupture or complication of a coarctation aneurysm. The majority of ascending aortic aneurysms are cloacal aneurysms. The principle of treatment is to remove the diseased segment of the ascending aorta and replace it with an artificial vessel or a homologous aorta. Since the procedure requires blocking the blood flow in the ascending aorta, care should be taken to protect the heart, brain, spinal cord and internal organs from ischemia and hypoxia, and the left ventricle from acute enlargement and failure due to blocked blood drainage. In cases of ascending aortic aneurysm with aortic valve insufficiency, aortic valve replacement, aneurysm removal and prosthetic vessel grafting are often required after removal of the aneurysm and aortic valve.