Inclusion Criteria:

          1. Voluntarily signed consent;

          2. Age of ≥ 18 and ≤ 80 years;

          3. Received sufficient prior lines of myeloma therapy;

          4. Received treatment with at least one proteasome inhibitor, one IMiD and daratumumab.

          5. The patients should have measurable disease per IMWG definition.

          6. Estimated life expectancy > 12 weeks;

          7. ECOG performance score 0-1;

          8. Patients should have reasonable CBC counts, renal and hepatic functions;

          9. Sufficient venous access for leukapheresis collection, and no other contraindications
             to leukapheresis;

         10. Women of childbearing age must undergo a serum pregnancy test with negative results
             before screening, and are willing to use effective and reliable method of
             contraception for at least 6 months after T cell infusion;

         11. Men must be willing to use effective and reliable method of contraception for at least
             6 months after T cell infusion.

        Exclusion Criteria:

          1. Pregnant or lactating women;

          2. HIV, active hepatitis C virus (HCV), or active hepatitis B virus (HBV) infection;

          3. Any uncontrolled active infection;

          4. AEs from previous treatment that have not recovered;

          5. Patients who have had anti-BCMA therapy;

          6. Patients who have graft versus host disease (GvHD);

          7. Patients have received stem cell transplantation less than 12 weeks before
             leukapheresis;

          8. Patients have received any anti-cancer treatment before leukapheresis;

          9. Patients have received steroids before leukapheresis or lymphodepletion;

         10. Patients have plasma cell leukemia, Waldenström macroglobulinemia, POEMS
             (polyneuropathy, organomegaly, endocrinopathy, monoclonal gammopathy, and skin
             changes) syndrome or clinically significant symptomatic immunoglobulin light chain
             (AL) amyloidosis with evidence of end-organ damage;

         11. Patients have been administered live attenuated vaccine before leukapheresis or
             lymphodepletion;

         12. Patients allergic to Flu, Cy, tocilizumab, dimethyl sulfoxide (DMSO) or CT053 CAR BCMA
             T cell;

         13. Patients have clinical significant cardiac conditions that researchers believe that
             participating in this clinical trial may endanger the health of the patients;

         14. Patients have clinical significant pulmonary conditions;

         15. Patients are known to have active autoimmune diseases including but not limited to
             psoriasis, rheumatoid arthritis and other needs of long-term immunosuppressive
             therapy;

         16. Patients with second malignancies in addition to MM are not eligible;

         17. Patients have central nervous system (CNS) metastases or CNS involvement;

         18. Patients have significant neurologic disorders;

         19. Patients are unable or unwilling to comply with the requirements of clinical trial;

         20. Patients have received major surgery prior to leukapheresis or prior to
             lymphodepletion.