Both epinephrine and isoprenaline are adrenergic receptor agonists, and adrenergic receptors are categorized into alpha and beta receptors. The action of, and difference between, epinephrine and isoprenaline is related to the distribution of the receptors and the effects of agonism. The difference between epinephrine and isoprenaline mainly includes the following points: First, the agonist receptors are different, epinephrine mainly agonizes the α-receptor and β-receptor, which can enhance myocardial contractility and elevate blood pressure. Isoprenaline mainly agonizes the β-receptor and has almost no effect on the α-receptor. Second, clinical application, epinephrine is mainly used in anaphylaxis, bronchial asthma and cardiac arrest rescue drugs, can also be used in glaucoma treatment. Isoprenaline is mainly used in bronchial asthma, atrioventricular block and infectious shock. Third, contraindications, epinephrine is contraindicated in patients with cardiogenic asthma, hypertension, hyperthyroidism, digitalis intoxication. Isoprenaline is contraindicated in patients with hypertension, hyperthyroidism, angina pectoris, coronary heart disease, myocarditis.