Abstract: Selenium is considered an important trace element related to human health. Cumulative evidence proves that selenium has an antioxidant property, which may reduce the risk of occurrence of some diseases including cardiovascular diseases. Clinically, selenium is reported to have accelerated the rehabilitation of patients with coronary heart disease and heart failure. Selenium deficiency is often found in patients with cardiovascular diseases. Studies have shown that selenium deficiency can interrupt the balance between oxidants and antioxidants mainly by influencing synthesis, modification and activities of certain selenoproteins such as glutathione peroxidase of the antioxidant system. Selenium supplementation would rebuild the balance between oxidants and antioxidants and reduce oxidative stress injuries. In addition, selenium plays a crucial role in the pathogenesis of cardiac arrhythmias, cardiomyopathy and myocarditis, although some mechanisms are not totally clear. Studies on selenium and heart disease would be helpful to basic research and contribute to the development of new drugs for cardiovascular diseases and to nutritional therapy for patients.