This study was aimed to explore feasibility and efficacy of unrelated donor peripheral blood stem cell transplantation (UD-PBSCT) in treatment of hematologic malignancies. Ten patients with hematologic malignancies underwent high resolution DNA based typing HLA-matched or 1 locus mismatched UD-PBSCT. Busulfan, cyclophosphamide, Ara-C, MeCCNU and antithymocyte globulin (ATG) were used for preconditioning regimen in all cases. All patients received mycophenolate mofetile, cyclosporin A and short-term methotrexate with CD25 antibody as the graft-versus-host disease (GVHD) prophylaxis. The results showed that rapid engraftment was observed in all cases who presented full donor chimerism at 28 days post transplantation by STR-PCR. The median time of neutrophil recovery > 0.5 x 10(9)/L, platelet recovery > 20 x 10(9)/L was 13, 17.5 days respectively after transplantation. The incidence of acute GVHD was 3 cases (one case with grade I was recovered from GVHD by himself, one case with grade III was cured, one case with grade VI was died). It is concluded that above-mentioned preconditioning regimen and GVHD prophylaxis are effective approaches for unrelated donor peripheral blood stem cell transplantation in hematopoietic malignancies.