The aim of this study was to explore the clinical effect and complications of allogeneic peripheral blood stem cell transplantation (allo-PBSCT) in hematologic malignancies through retrospective analysis of 75 patients (42 male, 33 female; aged from 13 to 72 years old) received allo-PBSCT from HLA matched (n=61) or haploidentical donors (n=14). 75 patients included 35 patients with chronic myeloid leukemia (CML), 30 patients with acute myeloid leukemia, 5 patients with severe aplastic anemia, 3 patients with acute lymphocytic leukemia, one patients with multiple myeloma and one patients with paroxysmal nocturnal hemoglobinuria. Conditioning regimens were (1) Cy/TBI or Bu/Cy; (2) Cy/TBI+Ara-C; (3) fludarabine+TBI/or (CTX+ATG). Minimal residual disease has been monitored regularly by PCR and FISH. Patients received cyclosporine A and methotrexate or ATG and anti-CD25 monoclonal antibody and mycophenolate mofetil for graft-versus-host disease (GVHD) prophylaxis. Relapsing patients after transplantation received DLI and/or chemotherapy. Patient with CML were treated with imatinib. The results showed that 74 patients had hematopoietic reconstitution, and eventually converted to full donor chimerism by FISH or PCR-STR. The median time for the initial hematopoietic reconstitution was 15 (5-25) days. 46 out of 75 patients were alive and median duration was 23 (2-61) months. Among 29 dead patients, 9 died of disease relapse, 7 died of III-IV grade of acute GVHD and 7 died of severe infection (2 patients developed interstitial pneumonia). 9 out of 14 patients received haploidentical transplantation were alive, and the time of event-free survival was 30 (6-53) months, the mean survival time of 5 died patients was 7 (2-17) months. 16 patients were infected by cytomegalovirus, 2 of them died of interstitial pneumonia. None of them suffered from veno-occlusive disease in the liver. It is concluded that allo-PBSCT is effective to treat refractory hematologic diseases, and DLI/or chemotherapy should be used in the patients relapsing after transplantation.