Inclusion Criteria:  Patients with AL must meet one of the following criteria ：A or B. A: relapse AL desease was defined as followes:(Reappearance of leukemic blasts in the pheripheral blood after CR or(2)detection of >5% blasts in the bone marrow (BM) not attributable to another cause(e.g.regeneration after consolidation therapy);or(3)extramedullary relapse.  B: refractory AL disease was defined as follows:(1):failure to attained CR following exposure to at least 2 courses of standed or intensive induction therapy,or(2)bone marrow leukemia cell decline index (BMCDI)<50% and>15% blast existence after one course of standed or intensive induction therapy.  patients without serious disease of heart or liver or lung or renals. sign informed consent voluntarily. Patients aged between 18 and 65 years old,male or female is permitted. ECOG performence status score less than 1. The expected survival is longer than 3 months.  Exclusion Criteria:  With other malignant tumors. Patients received the treatment of cladribine or venetoclax. Patients received cardiac angioplasty or stent implantation or h Active infections that are not under clinical control(bacteria or fungus or virus is included). Liver functions abnormilities (total bilirubin>1.5 times the upper limit of the the normal range,ALT/AST>2.5 times the upper limit of the normal range or patients with liver involvement whose ALT/AST>1.5 times the upper limit of the normal range),or renal anomalies(serum creatinine>1.5 times the upper limit of normal value). Pregnant or nursing women. Patieents with mental disorders or other conditions whereby informed consent cannot be obtained and where the requirements of the study treatment and procedures cannot be met. Patients participated in any other clinical trials 3 months prior to signing the informed consent. Patients not suitable for the study according to the investigator's assessment.