Aim To investigate the mechanism of glycogen synthase kinase 3β(GSK-3β)inhibitor lithium chloride on the proliferation of endothelial progenitor cells(EPC). Methods Mononuclear cells were isolated from bone marrow in rats by density gradient centrifugation combined. After 7 days, EPC were cultured with different concentrations of GSK-3β inhibitor lithium chloride. EPC proliferation were assessed by cells count and 3-{4,5-dimethylthiazol-2yl}-2,5-diphenyltetrazolium bromide (MTT) assay. The cell cycle of EPC was measured by fluorescence-activated cell sorting (FACS). The expression of phosphor-GSK-3β(pGSK-3β), β-catenin and cyclinD1 in EPC were detected by Western blot. Results Lithium chloride improved EPC proliferation. The number of EPC was obviously increased in lithium chloride group than that in control group. Compared with control group, EPC proliferation was enhanced in a dose-dependent manner in lithium chloride groups. S phrase in cell cycle was increased in lithium chloride group in comparison with control group by FACS assay. The protein expression of pGSK-3β, β-catenin and cyclinD1 were significantly higher than that in control group. Conclusion GSK-3β inhibitor lithium chloride could enhance EPC proliferation by activating Wnt signal pathway.