Aim To explore the effects and related mechanisms of testosterone on the proliferation of Peripheral-blood endothelial progenitor cells （PB-EPCs）. Methods Total mononuclear cells（MNC） were isolated from peripheral blood of healthy volunteers by Ficoll density gradient centrifugation, culturing with EGM-2MV for 7 days in vitro. The adherent cells showed up taking of acetylated low-density （ac-LDL-DiI） and binding of lectin（FITC-UEA-I）, observing with confocal laser scanning microscopy. PB-EPC were dealt with four concentrations of testosterone, as 0 nmol/L, 1 nmol/L, 10 nmol/L,and 100 nmol/L respectively, and in another group PB-EPC were pretreated with 10 nmol/L flutamide （androgen receptor antagonist） for 3h and then stimulated with 10 nmol/L testosterone. After 48 h, the ability of cell proliferation was determined by 3-（4,5-dimethylthiazol-2-yl）-2,5-diph-phenyltetrazolium bromide assay （MTT）. The VEGF expression was tested by quantitative real-time RT-PCR and ELISA assay. Results The proliferation of PB-EPC were increased by testosterone in a dose-dependent manner, however, these effects could be blocked by flutamide. Testosterone can up-regulate VEGF both on mRNA and protein level, however, these effects could be blocked by flutamide. Conclusions Testosterone enhances the proliferation of PB-EPCs by up-regulating VEGF expression via androgen receptor pathway.