Objective The outcomes of allogeneic hematopoietic stem cell transplantation(allo-HSCT)for myelodysplastic syndromes-evolved acute myeloid leukemia(MDS-AML)were explored.Methods A retrospective review was conducted for 54 patients with MDS-AML treated with allo-HSCT in the Institute of Hematology and Blood Disease Hospital from January 2018 to August 2022.The clinical effects after transplantation were observed,and the related risk factors influencing prognosis were explored.Results Of the total 54 patients,26 males,28 females,and 53 patients achieved hematopoietic reconstruction.After a median follow-up of 597(15-1 934)days,the 1 year overall survival(OS)rate,disease-free survival(DFS)rate,relapse rate(CIR)and non-relapse mortality(NRM)rate were(75.8±5.8)%,(72.1±6.1)%,(12.7±4.9)%,and(17.1±5.2)%,respectively.The 3 year estimated OS,DFS,CIR,andNRM rates were(57.8±7.5)%,(58.1±7.2)%,(23.2±6.6)%,and(23.7±6.6)%,respectively.The cumulative incidence of acute graft-versus-host disease(aGVHD)was(57.5±6.9)%,and the cumulative incidence of chronic graft-versus-host disease(cGVHD)was(48.4±7.7)%.Hematopoietic cell transplantation comorbidity index(HCT-CI)before transplantation was ≥2,minimal residual disease(MRD)was positive on the day of reconstitution,grade Ⅲ/Ⅳ aGVHD,bacterial or fungal infection and no cGVHD after transplantation were adverse prognostic factors for OS(P<0.05).COX regression model for multivariate analysis showed that HCT-CI score before transplantation,bone marrow MRD on the day of response,grade Ⅲ or Ⅳ aGVHD,and cGVHD after transplantation were the independent adverse factors for OS(P=0.001,HR=6.981,95%CI 2.186-22.300;P=0.010,HR=6.719,95%CI 1.572-28.711;P=0.026,HR=3.386,95%CI 1.158-9.901;P=0.006,HR=0.151,95%CI 0.039-0.581).Conclusion For patients with MDS-AML and high risk of relapse,allogeneic transplantation must be considered as soon as possible.The enhanced management of post-transplantation complications and maintenance treatment should be provided whenever possible after transplantation.