Compare the Efficacy and Safety of Dec-FB4 and FB4 as Conditioning Regimen for AML-MR

Inclusion Criteria:

* Age 16-65 years and with an ECOG physical fitness score of 0-2 and an HCT-CI of less than 3;
* Diagnosis: All enrolled cases were diagnosed with acute myeloid leukemia (AML-MR) after bone marrow cytomorphology, cytochemistry, immunophenotyping, chromosomal examination, and gene mutation, and achieved hematological remission (bone marrow smear primitive cells \<5%) and negative MRD before transplantation.
* Have a medically qualified and suitable hematopoietic stem cell donor, including HLA-allogamous sibling donors, unrelated donors (HLA high-resolution 9-10/10 compatible) or related haploidentical donors;
* No dysfunction of the heart, liver, lungs, kidneys, or other important organs, as defined as follows: ALT and AST ≤3 times the upper limit of normal; total bilirubin ≤2 times the upper limit of normal); BUN and Cr ≤1.25 times the upper limit of normal; electrocardiograms not suggestive of acute myocardial infarction or serious arrhythmias; cardiac echocardiography left ventricular ejection fraction ≥50%, no significant cardiac enlargement, valvular disease, or congenital heart disease; pulmonary function examination FEV1, FVC, DLCO ≥ 60% of the predicted value.
* The patient and his/her legal representative have the desire and requirement to undergo hematopoietic stem cell transplantation and sign an informed consent, willingness and compliance with the treatment plan, follow-up schedule, laboratory tests, etc.

Exclusion Criteria:

* AML in unremitting stage; or BM in remission but with concurrent CNS leukemia or presence of extramedullary lesions;
* Active hepatitis B (HBV-DNA ≥1×10\^3 copies/ml);
* HIV-infected patients;
* Active infections requiring intravenous antibiotic therapy;
* There is severe impairment of vital organ function: respiratory failure, heart failure, decompensated hepatic insufficiency, renal insufficiency, etc;
* Patients who use drugs or chronic alcohol abuse to the extent that it interferes with the evaluation of test results;
* Mentally challenged/unable to obtain informed consent;
* Those judged by the investigator to be unsuitable for participation in this trial.