Common causes of angina pectoris include coronary atherosclerosis, coronary artery spasm, other diseases of the coronary arteries and non-coronary artery diseases. 1. Coronary atherosclerosis leads to narrowing of the lumen or dislodgment of atheromatous plaque blocking the blood vessels, thus causing myocardial ischemia and leading to angina. 2. Coronary artery spasm, which is the main cause of variant angina pectoris, is a transient narrowing of the coronary arteries in the case of coronary artery spasm. 3. Other diseases of the coronary arteries, such as inflammation, malformation and thrombosis of the coronary arteries. 4. Non-coronary diseases. Aortic stenosis, aortic insufficiency, severe anemia, hyperthyroidism, syphilitic aortitis, hypotensive blood viscosity, hypertrophic obstructive cardiomyopathy, mitral valve prolapse, etc., may cause angina. The causes of angina pectoris are complex and varied, but coronary atherosclerosis and coronary artery spasm are common causes. Once the symptoms of angina occur, it is important to seek medical attention and timely treatment.