Coronary CT is a widely used clinical examination, especially in the screening of coronary heart disease. Coronary CT examination is mainly an auxiliary examination to check whether the arterial vasculature is normal. It is mainly applied in the following aspects: first, suspected coronary stenosis or hemodynamic abnormalities based on clinical examination; second, suspected coronary artery disease, the results of which cannot be determined by exercise test; third, suspected coronary artery anatomical abnormalities, such as congenital coronary artery abnormalities. For long-term unexplained chest pain, if other examinations do not reveal obvious abnormalities, even a triple CTA examination of the aorta, pulmonary artery and coronary artery can be done. In addition, medical examinations for special populations, including pilots and athletes. However, coronary CTA has certain limitations, and coronary angiography is preferred in cases of clear coronary stenosis or obvious ischemia. However, in some outpatients, coronary CT may be the first choice as CT or in some cases where the diagnosis of coronary artery disease is not particularly clear. Coronary CT is not suitable for everyone. It is not recommended to do coronary CT in elderly people with severe renal abnormalities, because coronary CT will have a contrast agent and may cause renal damage; it is also not recommended to do coronary CT for those with atrial fibrillation or obvious arrhythmias, because coronary CT is a gated system, and if it is arrhythmia or atrial fibrillation, coronary CT is not very accurate, and there are even significant differences. For those who have clear and obvious stenosis or after stenting, coronary angiography may be preferred.