Inclusion Criteria:  FLT3 positive relapsed/refractory acute myeloid leukemia Age 16-65 years. Left ventricular ejection fractions ≥ 0.5 by echocardiography Creatinine < 1.5x upper limit of normal. Aspartate aminotransferase/aspartate aminotransferase ≤ 2.5x upper limit of normal Total bilirubin ≤ 1.5x upper limit of normal Karnofsky performance status ≥ 60 Expected survival time ≥ 3 months (according to investigator's judgement)  Exclusion Criteria:  Patients are pregnant or lactating Uncontrolled active infection Grade III/IV cardiovascular disability according to the New York Heart Association Classification Active hepatitis B or hepatitis C infection Patients with HIV infection Patients with a history of seizure Patients with other contraindications considered unsuitable for participation in this study (according to investigator's judgement)