Inclusion Criteria:  Signed written informed consent; According to the international standard for multiple myeloma，have information on medical examination proving the diagnosis of multiple myeloma. Received at least 2 prior lines of treatment, including proteasome inhibitor and immunomodulator, no efficacy more than PD; disease progression or relapsed after disease remission and refractory or no remission after treated in the last time. Measurable disease at screening as defined by any of the following: Serum monoclonal paraprotein (M-protein) level ≥1.0 g/dL or urine M-protein level veing as defined ；or light chain MM without measurable disease in the serum or the urine；serum immunoglobulin free light chain isease dL and abnormal serum immunoglobulin kappa/lambda free light chain ratio ； ECOG Scores: 0~2（See Annex 3），the estimated survival time was more than 3 months; During the screening period, the clinical laboratory values met the following criteria： Hemoglobins70g/L (did not receive red blood cell transfusion ≤7 days prior to laboratory tests，recombinant human erythropoietin is allowed); Platelet count >50×10^9/L (did not receive blood transfusion ≤7 days prior to laboratory tests); Neutrophil absolute count oietin is (did not receive supportive treatment lowed); Platelet count >50×10^9/L，allowed to use over growth factor support); ALT and AST ≤3×ULN；Total bilirubin ≤2.0× UNL；Creatinine clearance×40mL/min；corrected serum calcium L/minctordL (3.1 mmol/L), or free calcium ion or freedL(L( ommol/L); Prothrombin time and activated partial thromboplastin time ≤1.5×ULN. The urine pregnancy test of female subjects of childbearing age should be negative and not in lactation; Females of childbearing potential and males must use efficient contraception（form signing the ICF to the end of the trial）  Exclusion Criteria:  Have received CAR-NK therapy； Have a history of allergy to any component of cell products; Previous history of other malignancy; Any unstable cardiovascular disease happened the informed consent form by themselves or their legal guardian;boratory tests); be infused using the "3 + 3" dos grade), severe arrhythmia that require drug interference, cardiac angioplasty/coronary stent implantation/cardiac bypass surgery ≤6 months prior to enrollment; Have received allogeneic hematopoietic stem cell transplantation in 3 months for the treatment of multiple myeloma; who has suffered from brain injury, consciousness disorder, epilepsy, more serious cerebral ischemia or cerebral hemorrhage disease; There were live vaccinations within 4 weeks before admission; Active hepatitis (positive for HBVDNA or HCVRNA), syphilis and other acquired and congenital immunodeficiency diseases, including but not limited to those with HIV infection; Oxygen is needed to maintain adequate oxygen saturation; Contraindications for fludarabine or cyclophosphamide treatment. There was uncontrolled active infection;Patients with autoimmune diseases, immunodeficiency or other diseases requiring immunosuppressive （excluding glucocorticoid）therapy; Pregnant or breasting-feeding women; Subjects had a history of alcohol, drug or mental illness; Any other condition that researcher think it is inappropriate for the subject to anticipate the trial.