Aim Oxidative modification of low density lipoprotein(LDL)has been proved to play a crucial.role in atherogenesis,In this paper,we studied the kinetic changes of several products produced during oxidative modification of LDL in vitro. Methods Oxidative modification of LDL was initiated by Cu2+ and kinetic changes of lipid hydroperoxides(LOOH),conjugated diene(CD),thiobarbrturic acid reactive substances(TBARS),relative electrophoretic mobility(REM) and fluorescence of LDL were determined. Results The content of TBARS,fluorescence in LDL and REM of LDL increased with the modification time,but the changes of LOOH and CD were different.Their kinetic changes showed three different phases:lag, propagation and decomposition. Conclusions The values of TBARS,REM and fluorescence of LDL could denote the extent of modification,but that of LOOH and CD cold not.By comparing the lag time,the susceptibility to the oxidative modification of LDL from different donors and the inhibitory effect of antioxidants on the oxidative modification could be studied.