A large number of clinical trials and data show that long-term use of beta-blockers is beneficial to patients with coronary artery disease. 1, angina: β-blockers are important drugs for the treatment of exertional angina, but should be contraindicated for variant angina. 2.Myocardial infarction: For acute myocardial infarction with rapid heart rate, low blood pressure and increased blood catecholamines, β-blockers are effective in limiting the expansion of the infarct and preventing arrhythmias. Beta-blockers can reduce the likelihood of nonfatal reinfarction and recurrent myocardial ischemia if applied within a few hours after myocardial infarction. Application of beta-blockers can reduce sudden cardiac death after myocardial infarction by approximately 20%, and this effect is independent of the timing of drug administration. Post-myocardial infarction patients with the following conditions may benefit from long-term β-blocker therapy (1) left ventricular insufficiency; (2) persistent myocardial ischemia, such as angina pectoris, abnormal post-infarction stress test, and severe stenosis of the coronary artery supplying the surviving myocardium; (3) certain arrhythmias; (4) comorbidities that can be treated with beta-blockers, such as hypertension, supraventricular tachycardia, and anxiety. 3, hypertension: β-blockers are the first-line drugs for the treatment of hypertension, and are indicated for sympathetic hypertension and high-renin hypertension, and also for patients with combined angina pectoris. 4, arrhythmia: beta-blockers are effective for atrial premature beats and ventricular premature beats, especially for arrhythmias related to sympathetic excitation.