Inclusion Criteria:  In order to be eligible to participate in this study, an individual must meet all of the following criteria:  Candidates with relapse or refractory CD33+ acute myeloid leukemia, who have progressed on after treatment with all standard therapies or intolerant of standard care, have limited prognosis with currently available therapies and had no available curative treatment options (such as HSCT or chemotherapy) Male or female, aged 1-70 years No serious allergic constitution Eastern Cooperative Oncology Group (ECOG) performance status (Oken et al.,1982) score 0 to 2 Have life expectancy of at least 60 days based on investigator's judgement CD33 positive in bone marrow or cerebrospinal fluid (CSF) by flow cytometry, or CD33 positive in tumor tissues by immunohistochemistry; (CD33 positive criteria: Flow cytometry: Positive: > 80% of tumor cells expressed CD33 and the MFI of CD33 is the same as that in normal myeloid cells; Dim: > 80% of tumor cells expressed CD33, but the MFI of CD33 is lower than that in normal myeloid cells as least as 1log; Partial positive: 20-80% of tumor cells expressed CD33 and the MFI of CD33 is the same as that in normal myeloid cells. Tumor tissue immunohistochemistry: Positive > 30% tumor cells expressed CD33); Provide a signed informed consent before any screening procedure; subjects who voluntarily participate in the study should have the ability to understand and sign the informed consent form and be willing to follow the study visit schedule and relevant study procedure, as specified in the protocol. Candidates aged 19-70 years need to be sufficiently conscious and able to sign the treatment consent form and voluntary consent form. Pediatric patients aged 1-7 years could be recruited after signing an informed consent form by a legal surrogate (Guardian); pediatric patients aged 8-18 years need to be sufficiently conscious and voluntarily signed an informed consent form, and their legal surrogates (guardians) were also required to sign a written informed consent form.  Exclusion Criteria:  An individual who meets any of the following criteria will be excluded from participation in this study:  Intracranial hypertension or disorder of consciousness Symptomatic heart failure or severe arrhythmia Symptoms of severe respiratory failure Complicated with other types of malignant tumors Diffuse intravascular coagulation Serum creatinine and / or blood urea nitrogen ≥ 1.5 times of the normal value Suffering from septicemia or other uncontrollable infections Patients with uncontrollable diabetes Severe mental disorders Obvious and active intracranial lesions were detected by cranial magnetic resonance imaging (MRI) Have received organ transplantation (excluding hematopoietic stem cell transplantation); Reproductive-aged female patients with positive blood HCG test Screened to be positive of infection of hepatitis (including hepatitis B and C), AIDS or syphilis Patients with tumor burden higher than 30% requiring reinfusion of autologous CAR-T cells.