Angina pectoris is graded according to the cause as well as the basis of its onset, and is called Braunwald’s angina pectoris classification. It can be divided into three levels: 1, grade I: initial exertional angina, this angina is an angina attack that occurs within 1 month, in the onset of the trigger, the mode of relief and the duration, the degree of attack is significantly aggravated, but there is no quiet state attack, this attack is below the daily activities only after the onset of angina symptoms; 2, grade II: unstable angina is a subacute unstable Angina pectoris, refers to the angina pectoris that has occurred in the prone position within 1 month, but has not occurred within the last 48 hours; 3, Grade III: acute unstable angina, has occurred within 48 hours of unstable angina, according to this different grading to assess the degree of unstable angina attacks and the risk, for whether to play a guiding role in the timely consultation.