This study was aimed to explore the effect and feasibility of reduced conditioning intensity allogeneic hematopoietic stem cell transplantation (allo-HSCT) in the treatment of relapsed ETO positive acute myeloid leukemia (AML) patients. Fifteen cases of relapsed AML received the reducing conditioning intensity allo-HSCT from January 2011 to January 2013 in Beijing Military Command General Hospital. All patients were high-risk type of relapsed or refractory AML, including 10 males and 5 females, aged from 16 to 48 years old with mean age of 32.5 years. Ten cases are HLA-identical matching and other 5 cases are HLA-haploidentical.donors received granulocyte colony-stimulating factor (G-CSF) to mobilize the peripheral blood stem cell for transplantation. Conditioning regimen was fludarabine combined with busulfex, cytarabine and cyclophosphamide. The preventive donor's peripheral blood stem cell infusion were performed after 3 months of transplantation, and the toxicity, GVHD and disease-free survival were observed in patients after transplantation. The results showed that all patients achieved hematopoietic reconstitution, the average time of neutrophils ≥ 0.5 × 10⁹/L and platelets ≥ 20 × 10⁹/L were 15.5 d and 16.8 d respectively. Implantation was confirmed by the evidence of 100% donor hematopoiesis. Follow-up to June 2014, with a median follow-up duration of 27.5 months (18-54 months), GVHD occurred in 8 cases of all patients, one died of complication, the other 4 cases died of relapse and the other three patients remained in disease-free survival. The disease-free survival rate of 2-year was 66.7%,the longest disease-free survival time was up to 54 months. It is concluded that the reduced conditioning intensity allo-HSCT is the effective and safe method for relapsed AML with ETO-positive, and it may be chosen as a treatment method for relapsed ETO positive AML patients.