Metoprolol has many roles, its mechanism is mainly by antagonizing the sympathetic excitation and play many roles, specifically, first, there is a role of antihypertensive, especially for patients with sympathetic excitation, antihypertensive effect is better. Second, metoprolol can be used in the treatment of coronary heart disease, as a member of the secondary prevention of coronary heart disease, can play a very important role, but also can reduce myocardial oxygen consumption, improve the symptoms of coronary heart disease patients with ischemia. Third, metoprolol can be used for antiarrhythmic treatment, which has a certain effect on supraventricular and ventricular arrhythmias, and can also slow down the ventricular rate. Fourth, metoprolol can be used in the treatment of heart failure, heart failure patients of the sympathetic nerve is excited, metoprolol as antagonism sympathetic very important a link, can improve the prognosis of patients with heart failure, and with ACEI, ARB, aldosterone receptor blockers to form a golden triangle, to improve the prognosis of a treatment.