Aim To observe the mechanism of oxidative modification of high density lipoprotein induced by cultured human arterial smooth muscle cell. Methods The oxidative modification of high density lipoprotein was identified by agarose gel electrophoresis mobility change, absorbance at 234 nm by ultraviolet light, level of lipid hydroperoxide by visible light and fluorescence of thiobarbuturic acid reaction substance of human plasma high density lipoprotein. Results The electrophoretic mobility of high density lipoprotein was increased and absorbance at 234 nm, lipid hydroperoxide and thiobarbuturic acid reaction substance of high density lipoprotein incubated by cultured human arterial smooth muscle cell were significantly higher than that of the native high density lipoprotein. Conclusion Oxidative modification of high density lipoprotein could be induced by cultured human arterial smooth muscle cell.