Aim To study the effect of oxidized low density lipoprotein on biological properties of smooth muscle progenitor cells. Methods Mononuclear cells were isolated from human peripheral blood and cultured with fibronectin,platelet-derived growth factor-BB and EGM-2 medium. Cellular immumofluorescence method and reverse transcription polymerase chain reaction(RT-PCR) method were used to indentify smooth muslce progenitor cells.Smooth muslce progenitor cells were cultured in medium respectively added with oxidized low density lipoprotein in 25,50,100,200 mg/L for 24 hours.Then MTT assay was used to detect cellular proliferational ability,cellular immumofluorescence method and RT-PCR method were used to detect the expression of α-smooth muscle actin. Results Smooth muscle progenitor cells grew with a hill and valley morphology.Smooth muscle progenitor cells could express smooth muslce cell specific biomakers such as α-smooth muscle actin and calponin.The proliferation ability of experimental groups was significantly higher than that of the control group.Especially when the concentration of oxidized low density lipoprotein was 50 mg/L,the proliferation ability of smooth muscle progenitor cells was the highest.The expression of α-smooth muscle actin in experimental group was less than that in control group. Conclusion Oxidized low density lipoprotein can stimulate proliferation and decrease α-smooth muscle actin expression of smooth muscle progenitor cells.