Abstract: Objective To investigate the migration function of ex vivo expanded endothelial progenitor cell (EPC) by stromal cell-derived factor-1 (SDF-1). Methods Total mononuclear cells were isolated from human peripheral blood by density gradient centrifugation. Attached spindle -shaped cells were detached at day 7. The expression of CD34 and CD133 were determined by flow cytometry; KDR(VEGFR-2) was detected by reverse transcriptase-polymerase chain reaction; endothelial function was determined by cell absorption of DiI-acLDL and FITC-UEA-1; the expression of CXCR4 was determined by immunocytofluorescence. The migration function of EPC was determined using Transwell chamber. Results The positive rates of CD34, CD133 of EPC at 7 days of culture were 36.3%±23.8% and 19.7%±10.3% respectively. RT-PCR demonstrated the presence of KDR mRNA. EPC had the capacity to incorporate DiI-acLDL and FITC-UEA-1 ( >90% ). The expression of CXCR4 receptor was 74.8%. The migration cells of control, 10, 20 and 50μg/L were 3.5, 7.4, 24.9 and 28.0, respectively. The migration activity was significantly higher in groups of SDF-1 than that of control group (p<0.01). The difference was determined in comparison of 10μg/L vs 20μg/L (p<0.01), 20μg/L vs 50μg/L (p<0.05), and 10μg/Lvs 50μg/L (p<0.01), respectively. Conclusions 1. EPCs could be isolated and cultured from peripheral blood mononuclear cells. The CXCR4 receptor is present on EPC. 2. SDF-1 induces EPC migration in a dose-dependent manner.