The angina attack in the middle of the night is mainly considered to be recumbent angina or variant angina, both of which belong to unstable angina. The angina attack in the middle of the night does not have any relationship with the activity, and most of the patients are at rest or sleeping, when angina occurs, it is related to the occurrence of spasm in the coronary vessels of the heart. The occurrence of coronary spasm means that the heart blood vessels have slight narrowing or no narrowing at all, and the relative ischemia of the heart is caused by the contracture of blood vessels. ECG examination is mainly to determine whether there is any obvious change in the ECG at rest, when there is no seizure, and the ECG during the onset of chest pain. If ST-segment change or even transient ST-segment elevation is found, it is more likely to consider variant angina. Such patients are strictly forbidden to use nitroglycerin to dilate the coronary heart, because there is no obvious effect, and should be treated with calcium antagonists, which can play a role in vasodilatation.