Typical angina pectoris has its own distinctive features in terms of pain location, nature, triggering factors, duration and relief, which is an important marker to distinguish it from other chest pains. Clinically, there are many causes of chest pain and various characteristics of pain: 1. Stabbing pain for a few seconds or pain that lasts for hours or even days. 2.The range of chest pain is not a piece, but a point, and a finger can be used to point out the location of the pain. 3.Pain mostly appears after exertion, not at the time of exertion. 4.Thoracic pain is related to breathing or other movements that affect the thorax. 5.Thoracic pain can be transferred by other factors, such as talking with the patient to make his chest pain symptoms better instead. 6.The pain attack does not affect the activity. 7.The episodes of sublingual nitroglycerin are seen to be relieved only after 10 minutes.