This study was aimed to investigate whether aspirin has effect on function of late endothelial progenitor cells (EPC). Cord blood CD34(+) cells were purified using the ficoll density gradient centrifugation and human CD34 positive selection kit, then the cells were inoculated on fibronectin-coated culture plate. After culture for 2 weeks, adherent cells were identified as EPC by flow cytometry, immunofluorescence, RT-PCR, uptake of Dil-Ac-LDL and matrigel tube formation assay. EPC were treated with different concentrations of aspirin (0.1, 1, 10, 100, 1 000, 10 000 µmol/L) for 24 h, then the proliferation, adhesion and migration ability of these cells were analyzed by CCK-8 assay and transwell methods. The results indicated that the low concentrations of aspirin (0.1 and 1 000 µmol/L) promoted late EPC adhesive and migratory capacity, but no obvious effect on proliferation of late EPC were observed. On the other hand, the high concentrations of aspirin (10 000 µmol/L) inhibited proliferation and migratory capacity of EPC, but had no obvious effect on adhesive ability of EPC. It is concluded that low concentration of aspirin promotes migration and adhesion of late EPC, while the high concentration of aspirin decreases EPC proliferation and migratory capacity of EPC.