Coronary artery stenosis is a narrowing of the lumen of the coronary arteries due to atherosclerosis. The main clinical modality to confirm coronary artery stenosis is multilayer spiral CT coronary artery imaging. The gold standard for coronary artery stenosis is invasive coronary angiography. Coronary artery stenosis is divided into different degrees, and the degrees are classified mainly to guide clinical treatment. Grade I: refers to luminal stenosis of less than 25%. Grade II: is a luminal stenosis between 25% and 50%. Grade III: refers to luminal stenosis between 51% and 75%. Grade IV: is a luminal stenosis of 76% or more. We believe that if you want to diagnose a patient with coronary artery disease, then you need to have a stenosis greater than 50%. When coronary artery stenosis is fixed, or when the vascular resistance increases, it can lead to a reduction in coronary blood flow, especially when the stenosis is greater than 50%, the patient can compensate for it at rest, but if he or she is active or excited, the myocardial oxygen demand will increase, leading to an angina attack. If the luminal stenosis is greater than 70% to 75%, the blood supply will be seriously affected, and at this time we should actively perform coronary interventions to solve the lesioned vessels early and perform coronary stent interventions. For patients who are too sick to undergo coronary intervention, coronary artery bypass grafting should be performed as early as possible. Regardless of whether surgery is performed or not, once coronary artery stenosis is detected, we must actively treat it with secondary prevention drugs. As the most important basic treatment, secondary prevention drugs should be taken on a regular basis to prevent the progression of the disease by taking antiplatelet, anti-atherosclerotic, lipid-lowering, plaque stabilizing and endothelial function improving drugs.