Objective To investigate the feasibility of haploid genetic allogeneic hematopoietic stem cell transplantation in the treatment of severe aplastic anemia(SAA) in our hospital. Methods A 12-year-old patient with acquired SAA for 4 years showed no response to CsA and cord blood transplant treatment and was transfusion-dependent. Lacking an HLA-identical sibling donor, the patient was treated with HSCT from his brother 5/10 matched at the generic level. Theconditioning regimen was BU+CTX+ATG:BU 3.2 mg/kg×2 d,CTX 50 mg/kg×4 d,ATG 2.5 mg/kg×4 d. Stem cells were the source of G-CSF mobilization of bone marrow and peripheral blood stem cells, dose of stem cells infused: mononuclear cells (MNC) 4.055×10⁸/kg (body weight of subject), CD34 2.331×10⁶/kg. Prevention of GVHD: -1 d Third-party umbilical cord blood cells which were HLA partially matched were used. Postoperative joint use included cyclosporine A, short-course methotrexate, mycophenolate mofetil. Results Hematopoiesis was slowly rebuilding, 22 d after surgery (+22 d) ANC> 0.5×10⁹/L, after three months departing from transfusion of platelets. +26 d suggesting that the DNA fingerprints showed donor genotypes. +40 d into donor blood type “O” type. + 29 d occurred acute GVHD (GI type, Ⅲ degrees), + 31 d, + 34 d + 42 d infusion of basiliximab 20mg, + 40 d, + 44 d, + 63 d infusion of mesenchymal stem cells. Gradually acute GVHD was controlled in the patient, who had lung infections, oral mucositis and cytomegalovirus viremia, could be controlled with anti-infective. Now followed up for 3 years, hemogram change has been normal and stable. Kamofsky score was 100 points. Conclusion It may be considered to have haploid genetic allogeneic hematopoietic stem cell transplantation for treatment of SAA, for those patients who have non-matched donor (including relatives and non-relatives) and potent immunosuppressive therapy failure. GVHD and infection are major complications. Need to adopt appropriate measures in accordance with the patient's condition.