Objective@#To investigate the safety and efficacy of allogeneic hematopoietic stem cell transplantation (allo-HSCT) containing cladribine sequential busulfan regimen for refractory/relapsed acute myeloid leukemia (AML) .@*Methods@#The clinical data of 12 refractory/relapsed AML patients received allo-HSCT with cladribine sequential busulfan regimen.@*Results@#① Of the 12 patients, 9 were males and 3 females, with a median age of 36 (27-50) years. The donors were identical sibling (3) , matched unrelated (1) and haploidentical family member (9) respectively. Nine patients reached partial remission and other remained no remission after chemotherapy before allo-HSCT. The median previous chemotherapy courses before allo-HSCT were 6 (2-13) . ② Conditioning regimen: Smostine 250 mg·m-2·d-1, d-7; Cladribine 5 mg·m-2·d-1, d-6 to d-2; Cytarabine Arabinoside 2 g·m-2·d-1, d-6 to d-2; Busulfan 3.2 mg·m-2·d-1, d-6 to d-3; Rabbit anti-human thymocyte immunoglobulin (ATG) 1.5 mg·m-2·d-1 (unrelated donor transplantation) or 2.0-2.5 mg·m-2·d-1 (haplo-HSCT) , d-4 to d-1. ③ Of the 12 patients, 11 patients attained complete haploidentical engraftment, one case occurred primary graft failure. The median durations for neutrophils and platelet implantations were 15 (15-21) and 19 (17-30) days respectively. ④After conditioning, no hepatic veno-occlusive diseases were observed, hemorrhagic cystitis occurred in 2 patients, 8 patients had fever, 3 cases experienced acute GVHD grade II, localized chronic GVHD occurred in 8 patients. ⑤The median follow-up was 8 (4-12) months. Leukemia relapse occurred in 2 patients at time of 6, 12 months after allo-HSCT. The estimated 1-year OS and DFS were (71.1±1.8) % and (62.2±1.8) %, respectively.@*Conclusions@#allo-HSCT with cladribine sequential busulfan regimen was a feasible choice with favorable outcome for refractory/relapsed AML.