Inclusion Criteria:  Documented acute myeloid leukemia according to World Health Organization（WHO） criteria(excluding acute promyelocytic leukemia), with FLT3-ITD gene mutation,refractory after common or enhanced chemotherapy or relapse. ECOG performance status of 0-1.  Subjects must have adequate organ function and meeting all of the following laboratory review before enrollment：  Lood routine examination: WBC≤2000/mm3; Liver function: Alanine aminotransferase (ALT) and Aspartate transaminase (AST) ≤2.5×upper limit of normal(ULN); serum bilirubin ≤ 1.5 × ULN; Renal function: Serum creatinine ≤ 1.5×ULN, or the creatinine clearance (CrCl)≥ 60 mL / min calculated by the Cockcroft-Gault formula; Electrolyte: serum potassium≥3.0mmol/L; serum calcium≥2.0 mmol/L;serum magnesium≥0.5 mmol/L; Coagulation function:fibrinogen≥1.0g/L; activated partial thromboplastin time( APTT)≦ULN+10s; prothrombin time(PT)≤ULN+3s.  Exclusion Criteria:  Received FLT3 inhibitors within 4 weeks prior to the administration; Received hematopoietic stem cell transplantation within2 months prior to the administration or received immunosuppressor beceause of GVHD; Chemotherapy, immunotherapy, radiotherapy, or major surgery within 4 weeks prior to administration; Nitrosourea and mitomycin chemotherapy within 6 weeks prior to the administration; Have taken live vaccines within 4 weeks prior to /or concurrent with the administration; Have received a trial investigational product, or participated in other clinical trials within 4 weeks prior to administration; Documented promyelocytic leukemia (t (15; 17) (q22; q11) and / or promyelocytic leukemia(PML)/retinoic acid receptor alpha (RARa) positivity found in the chromosome, variant acute promyelocytic leukemia; With myeloid sarcoma or invasion of central nervous system; NCI CTCAE 4.03 ≥ 2 grade of arrhythmia, or corrected QT interval(QTc )> 450 ms ; patients with a history of torsion or congenital QT prolonged syndrome; active infectious disease judged by the investigator.