Background: Refractory/Relapsed acute myeloid leukemia (R/R-AML) typically exhibits resistance to conventional chemotherapy, resulting in a poor overall therapeutic outcome, salvage allogeneic hematopoietic stem cell transplantation (allo-HSCT) is the primary treatment option in such patients. However, post-transplant relapse is still a challenge, with no established effective regimens. Case: In this case report, we present the case of a 40-year-old male diagnosed with R/R-AML who underwent salvage allo-HSCT. Unfortunately, after 4 months of follow-up, a relapse occurred. we modified the immunosuppressive therapy and administered donor lymphocyte infusion (DLI) and decitabine but failed to obtain complete remission (CR). Subsequently, a combination of venetoclax (Ven) and azacitidine (Aza), followed by the DLI regimen, was initiated. The patient achieved CR with no measurable residual disease. Conclusion: Our data suggests that the administration of Ven in combination with Aza followed by the DLI regimen used for early post-HSCT relapsed AML could serve as a valuable reference for treating similar patients.