The diameter of the giant coronary artery aneurysm is at least 4 times bigger than that of the normal coronary artery and 2-3 times bigger than that of the normal coronary artery aneurysm. Giant coronary artery aneurysm is rare in clinic with a reported morbidity which is less than 0.3%. Just like ordinary coronary artery aneurysm, coronary artery atherosclerosis is the main cause of the giant coronary artery aneurysm. Most giant coronary artery aneurysms are asymptomatic, but some patients may have heart-related clinical emergency in short term and may have thrombosis which can lead to embolism and fistula which can cause rupture in long term. Surgical treatment is the first chioce for giant coronary artery aneurysm now. However, the interventional therapy will also be an important way to treat the disease in the future. In this article, we review the diagnosis, clinical manifestation, treatment and other aspects of giant coronary artery aneurysm as follows.