Coronary angiography is the gold standard for the diagnosis of coronary artery disease. If coronary angiography reveals that the stenosis of the blood vessel is around 50%, it is a diagnosis of coronary artery disease. For a stenosis of about 50%, which only just meets the diagnostic criteria for coronary artery disease, the patient may choose to continue to apply medication. If the stenosis reaches 75% or more and there are clear symptoms of ischemia or evidence of ischemia on the ECG, stent implantation therapy may be an option. If the coronary stenosis is about 50%, drug therapy can be chosen unless there are special circumstances, such as recurrent angina pectoris and myocardial ischemia, which may require further interventional treatment. The main drug is to apply antiplatelet, lipid-lowering and plaque stabilizing drugs to control the progression of coronary artery disease.