This study was purposed to evaluate the curative efficacy of second allogeneic hematopoietic stem cell transplantation (allo-HSCT) after failure of the first allo-HSCT in aplastic anemia patients, the cause of implant failure after allo-HSCT and clinical data of 10 severe aplastic anemia (SAA) patients in the second allo-HSCT were retrospectively analyszed. The second HSCT conditioning programs include: cyclophosphamide (CTX) + fludarabine (FLU)+ anti-thymocyte globulin (ATG) combination chemotherapy for 3 cases; CTX + FLU + white busulfan (Bu) + ATG combination chemotherapy for 7 cases. The prevention regimen of graft-versus-host disease (GVHD) include cyclosporine (CsA), mycophenolate mofetil (MMF) and methotrexate (MTX). The median count of mononuclear cell infusion was 12.17 (5.99-18.12)×10(8)/kg. The CD34(+) cell count was 5.2 (3.8-10.9)×10(6)/kg. The results showed that 10 evaluable patients achieved hematopoietic reconstitution with absolute neutrophil >0.5×10(9)/L, platelets >20×10(9)/L at 15d (8-21d) and 17d (11-27d) after transplantation. The grade I aGVHD occurred in 2 case, grade II in 1 case, chronic GVHD in 3 cases. Transplant-related deaths occurred in 4 cases. The disease-free survival rate, transplant-related mortality, GVHD after transplantation were 60%, 40% and 50% respectively. It is concluded that the second allo-HSCT is an effective therapy for aplastic anemia after allo-HSCT implant failure.