Competitive inhibition of Angiotensin Converting Enzyme has an important role in cardiovascular diseases, which has been demonstrated by various extensive studies. Based on pharmacologic and mechanism of action, the pharmacodynamic of ACE-inhibitor involves some specific system, such as hemodynamic, neurohormonal, anti- proliferation and renal effect, etc. ACE-inhibitor has beneficial effect in various cardiovascular diseases such as heart failure, hypertension, systolic and dyastolic left ventricle dysfunction and acute myocardial infarction. This article will discuss advantages of its therapeutic use, the adverse effects that might occur as well as how to overcome this effect and also when it should be stopped. Extensive studies also demonstrate that therapeutic use of ACE-inhibitor will improve the quality of life and survival rate in conjunction with the decrease of morbidity and mortality.