The cultured porcin artery smooth muscle cells became foam cells by preeincubated with 10 mg·L-1 oxidized low density lipoprotein for 72 hours, which could accumulate cholesteryl ester and the ratio between cholesteryl ester and total cholesterol was 64. 1%. When the foam cells were incubared with 0. 01 mg·L-1 and 0. 1mg·L-1 Xiaoban peptide for 24 hours, they reversed to normal smooth muscle cells, whose ratio between cholesteryl ester and total choles terol was less than 50%. The amount of nitric oxide increased in the medium of foam cell and decreased in the proess of reversing to normal level. It suggest that Xiaoban peptide may be a new antiatherosclerosis medicine.