Spontaneous angina is an episode of chest pain unrelated to activity and is relatively difficult to diagnose compared to exertional angina. Exertional angina is relatively easy to diagnose if it has a definite trigger and can be relieved after a few minutes of rest or with medication. If the chest discomfort is not related to activity or emotional excitement, the first thing to do is to clarify whether there is angina pectoris. Of course, if it is clear that it is spontaneous angina and the attack ECG has obvious changes of myocardial ischemia, the diagnosis of spontaneous angina will be considered. Spontaneous angina belongs to a kind of unstable angina. The occurrence of angina attacks without an increased heart burden often suggests that the heart vessels may be narrowed more severely and the plaque is unstable, so it is a kind of unstable angina, which may progress to myocardial infarction if not handled properly, and usually the more frequent the attacks, the more serious the condition is suggested, such as repeated attacks within 48 hours, which requires special care.