Aim To investigate the effect of water extract propolis(WEP) on apoptosis in human umbilical arterial smooth muscle cell(HUASMC),and explore the mechanism of water extract propolis on inhibition of atherosclerosis and it's implications. Methods HUASMC were cultured and identified by immunocytochemistry technique.Cultured HUASMC were randomly divided into 5 groups: control group,model group and WEP groups(treated with 50 mg/L,100 mg/L and 200 mg/L WEP respectively).Intracellular total cholesterol(TC) and free cholesterol(FC) were measured by high performance liquid chromatogram,the content of cholesterol ester(CE) was obtained by subtracting the FC from TC.Cellular apoptosis index was tested by flow cytometry. Results The content of intracelluar CE in model group was more than that in control group(P<0.01).The content of intracellular CE in 50 mg/L,100 mg/L and 200 mg/L WEP groups were less than that in the model group(P<0.01),and with the increase of the concentration of WEP the content of intracellular CE showed the decreasing tendency.The cell apoptosis index in model group was higher than that in control group(P<0.01).The cell apoptosis index in 50 mg/L,100 mg/L and 200 mg/L WEP groups were lower than that in the model group(P<0.01),and with the increase of the concentration of WEP the cell apoptosis index showed the decreasing tendency.The content of intracellular CE was correlated with the cell apoptosis(r=0.964,P<0.01). Conclusion WEP can reduce the apoptosis of HUASMC induced by ox-LDL which may be concerned with the inhibination of intracellular CE accumulation.