• The subjects volunteered to join the study and signed informed consent form (ICF)with good compliance;

• Age: ≥ 18 years old (when signing ICF); ECOG PS score: 0-1; The expected survival period is more than 3 months;

• Multiple myeloma with diagnostic records and meeting the IMWG diagnostic criteria;

• In the presence of measurable lesions, at least one of the following criteria must be met:

‣ Serum monoclonal immunoglobulin (M protein)≥1.0g/dL,or urine M protein≥200mg/24h;

⁃ Light chain type: serum immunoglobulin free light chain (FLC) ≥ 10 mg/dL, and the ratio of free light chain serum immunoglobulin κ and λ is abnormal;

• Relapsed or refractory multiple myeloma who have received at least 1 line of therapy in the past, and are refractory to at least 1 proteasome inhibitor (PI), 1 immunomodulator (IMiD) and 1 CD38 monoclonal antibody;

• Disease progression during or within 12 months after the last treatment (meeting the PD criteria of IMWG), including refractory or no remission of the last treatment (≥1 cycle) or disease progression within 6 months;

• Major organ function is good;

• Female subjects of childbearing age should agree to use contraceptive measures (such as intrauterine devices, contraceptives or condoms) during the study period and within 6 months after the end of the study; serum pregnancy/urine pregnancy test within 7 days before study enrollment;