The main symptom of angina is paroxysmal chest tightness and chest pain. Clinical performance is mostly based on chest pain, but there are a few people who only feel chest tightness. The site, nature and duration of chest pain and the trigger have certain characteristics: 1. Site of chest pain: The typical site is in the upper middle part of the sternum, and the pain is not limited in scope, about the size of fist and palm. It can also occur outside the chest, and pain or discomfort in the upper abdomen (under the saber) is common; secondly, it can radiate to the left in the left chest, left back, left shoulder, left upper arm front inner side straight to the ring finger and little finger; it can also radiate upward to the neck, pharynx, jaw, teeth and head; radiate downward to the abdomen; radiate to the right to the right shoulder and arm. 2.Nature of chest pain: The nature of pain is constricting and squeezing sensation, smothering and suffocating sensation, occasionally with near-death-like fear, forcing patients to stop activities immediately. 3.Duration and relief mode: the pain lasts about 3-5 minutes, usually not more than 20 minutes. The symptoms can be relieved within 1-3 minutes after resting or taking nitroglycerin. 4, attack triggers: often triggered by exertion, exertion, satiety, cold, emotional excitement, etc.; but quiet and lying down state can also occur. 5, concomitant symptoms and combined diseases: chest pain is often accompanied by anxiety and fear of dying; patients with a history of diabetes, hypertension and hyperlipidemia should be highly suspicious of angina pectoris. The symptoms of angina pectoris are mainly manifested as paroxysmal chest tightness and chest pain. If the above typical symptoms exist, chest pain is relatively easy to identify angina, but clinical chest pain conditions are more difficult to identify. Patients with risk factors should be alert to angina when chest pain occurs and need to be seen in a timely manner.