Inclusion Criteria:  Age 18-75 (≥18, ≤75) one year old, no gender limit; The subject voluntarily participates in the study, and he or his legal guardian signs the "Informed Consent"; Definitely diagnosed as relapsed or refractory multiple myeloma: use chemotherapy regimens containing bortezomib, or chemotherapy regimens containing lenalidomide, the treatment is ineffective, or the disease progresses within 60 days after the end of the last chemotherapy; The patient has one or more measurable multiple myeloma lesions, which must include any of the following:  1) Serum M protein is greater than or equal to 0.5g / dl (10g / l) 2) Urine M protein is greater than or equal to 200 mg / 24 h serum FLC ratio is abnormal 3) Serum free light chain (FLC) ≧5 mg / dL (50 mg /L) 4) Plasmacytoma that can be measured by physical examination or imaging examination 5) Myeloma cells in bone marrow ≧10% by flow cytometry or immunohistochemical examination 5. After flow cytometry or immunohistochemical examination, myeloma cells have positive BCMA expression; 6. No salvage chemotherapy was used within 4 weeks before cell therapy; 7. Within 2 weeks before cell therapy, have not received antibody drug therapy; 8. The ECOG score is 0-2 points; 9. The subject has no contraindications to peripheral blood apheresis; 10. The expected survival period is ≧12 weeks; 11. Female subjects of childbearing age must have a negative urine pregnancy test within 7 days prior to cell therapy and not during the lactation period; female or male subjects of childbearing age must take effective contraceptive measures throughout the study.  Exclusion Criteria:  Those who have a history of allergies to any of the ingredients in cell products; The following conditions in laboratory tests: including but not limited to serum total bilirubin ≥ 1.5 mg/dl; serum ALT or AST greater than 2.5 times the upper limit of normal; blood creatinine ≥ 2.0 mg/dl; hemoglobin <80g/ l; does not rely on GCSF or other growth factors, the absolute neutrophil count is less than 1000 / mm3; no blood transfusion is required, and the platelet count is less than 30,000 / mm3; According to the New York Heart Association (NYHA) cardiac function classification standards, patients with grade III or IV cardiac insufficiency; or echocardiographic examination of left ventricular ejection fraction (LVEF) <50%; Abnormal lung function, blood oxygen saturation in indoor air <92%; Myocardial infarction, cardiovascular angioplasty or stenting, unstable angina, or other serious clinical heart diseases within 12 months before enrollment; Hypertension is grade 3 and the blood pressure is not well controlled by medication; Patients with prolonged QT interval on ECG, patients with severe heart disease such as severe arrhythmia in the past; Previously suffering from head injury, disturbance of consciousness, epilepsy, more serious cerebral ischemia or cerebral hemorrhage disease; Need to use any anticoagulant (except aspirin); Patients who need urgent treatment due to tumor progression or spinal cord compression; Patients with CNS metastasis or CNS involvement symptoms (including cranial neuropathy and extensive disease or spinal cord compression); The investigator determines that there are serious complications or diseases that increase the risk of the subject or affect the research, including but not limited to, for example: liver cirrhosis, recent major trauma, etc.; After allogeneic hematopoietic stem cell transplantation; Plasma cell leukemia; Before apheresis and within 2 weeks before CAR-T cell infusion, apply more than 5 mg/d of prednisone (or an equivalent amount of other corticosteroids); Patients with autoimmune diseases, immunodeficiencies or other patients who need immunosuppressive therapy; There is an uncontrolled active infection; Have used any CAR-T cell products or other genetically modified T cell therapies before; Live vaccination within 4 weeks before enrollment; HIV, HBV, HCV and TPPA/RPR infected persons, and HBV carriers; The subject has a history of alcoholism, drug abuse or mental illness; The subject has participated in any other clinical research within 3 months before joining this clinical research; The researcher believes that the subjects have other conditions that are not suitable for participating in this study.