The effect of Selenium(Se) on regression of atherosclerosis(AS) induced by feeding quails -with high cholesterol diet was observed. The result indicated that serum cholesterol, triglyceride and lipid peroxide significantly decreased and the ratio of high density lipoprotein cholesterol/total cholesterol increased markedly in Se treated group, that the cholesterol content of aortic tissue and AS index were significantly reduced at the end of the 15th week. It was suggested that Se had a powerful accelerated effect on regression of experimental AS.