【Abstract】Objective To investigate the effects of different concentrations of oxidized lowdensity lipoprotein (oxLDL) on the growth of human aortic smooth muscle cells (HAVSMC) at different time in vitro, analyze the optimal concentration and time of oxLDL to induce HAVSMC forming foam cells, and provide a basis for establishing an in vitro cell models for atherosclerosis and related disease research. Methods In this study, different concentrations of oxLDL (15 μg/ml and 20 μg/ml) were used to treat VSMC at different times (36 h, 48 h, 60 h, 72 h, 84 h and 96 h). The formation of foam cells were evaluated by determining the total cholesterol and cholesterol ester content as well as by oil red O staining to observe the intracellular lipid vacuoles. Meanwhile, the change of cell viability was detected by thiazolyl blue colorimetric assay (MTT assay). Results The content of total cholesterol and cholesterol ester, the ratio of cholesterol ester to total cholesterol, and lipid vacuoles increased with the increase of ox LDL concentration and treatment time. The ratio of cholesteryl ester / total cholesterol in 15 h g/mL ox LDL was more than 50% and the formation of lipid vacuoles indicated foam cell formation. At the same time, compared with the control group, the effect of 15 g/mL ox LDL on 36 and 48 h promoted cell proliferation, and the cell viability was significantly increased (P＜005). The vitality of 60, 72 and 84 h cells did not change significantly. The treatment of H H pairs showed that there was no significant change in the cell viability of the 60 h cells. Cell proliferation was inhibited and cell viability decreased significantly (P＜005), which indicated that the cell model of 15 μg/mL ox LDL treatment was not successful. The ratio of cholesteryl ester/total cholesterol in 20 h g/mL ox LDL was more than 50% and the formation of lipid vacuoles indicated the formation of foam cells. At the same time, compared with HA VSMC treated with 15 g/mL ox LDL, the activity of 36 36 cells in 20 g/mL g/mL ox treatment cells was significantly reduced (0, 01), 48, 60, 72 and LDL cells increased significantly. There was no significant change in 96 h cell viability. The cells were treated with 20 μg/mL ox LDL for 48, 60, 72 and 84 hours.Conclusion The activity of HA VSMC cells treated with ox LDL at a concentration of 20 μg/mL for 48 hours increased most significantly, which could be used as the best induction time and concentration for establishing as cell model in vitro.