BACKGROUND: In recent years, genetic haploidentical peripheral blood stem cell transplantation has been gradually improved, and haploid allogeneic hematopoietic stem cell transplantation has become an important treatment choice for malignant hematopoietic disease. OBJECTIVE: To observe the clinical efficacy of genetic haploidentical peripheral blood stem cell transplantation for myelodysplastic syndrome. METHODS: The clinical data of 21 myelodysplastic syndrome cases undergoing genetic haploidentical peripheral blood stem cell transplantation were retrospectively analyzed. Modified BU/CY+ATG administration was performed as a pretreatment strategy for haploidentical peripheral blood stem cell transplantation, and the combined use of cyclosporine A+mycophenolate mofetil+short-range methotrexate±basiliximab was adopted to prevent graft-versus-host disease (GVHD). RESULTS AND CONCLUSION: (1) The 21 cases were followed for an median of 333 days (22-1 222 days), with 76% (16/21) infection of granulocyte lack period, 100% (21/21) neutrophil reconstruction, the median implantation time of 12 days (7-17 days), 81% (17/21) platelet engraftment, and the median implantation time of 14 days (7-68 days). (2) The accumulative incidence of GVHD was 52.4% (11/21), including 29% (6/21) of acute GVHD and 24% (5/21) of chronic GVHD. The incidence of hemorrhagic cystitis was 38.1% (8/21). The recurrence rate after transplantation was 4.8% (1/21). (3) The 2-year non-relapse mortality was 48% (10/21), and the 2-year disease-free survival rate was 46.8%. These results show that in the absence of HLA-identical related donors and unrelated donor, genetic haploidentical peripheral blood stem cell transplantation is a safe, effective, feasible and alternative treatment option for myelodysplastic syndrome. [ABSTRACT FROM AUTHOR]