• Understand and comply with the research requirements, voluntarily participate in the research and sign the informed consent form before starting the relevant procedures;

• Age ≥ 18 and \< 75 years old at screening, gender not limited;

• Positive anti-ANA antibody and/or anti-dsDNA antibody (research center);

• Pathological type of active III or IV lupus nephritis confirmed by renal biopsy within 12 months before screening, with or without type V (adopting the 2003 International Society of Nephrology/Renal Pathology Working Group's lupus nephritis pathological classification criteria, see Appendix 2; for recurrent subjects, the investigator assesses whether a repeat renal biopsy is necessary; renal biopsy is conducted after confirming that the subject meets all other inclusion criterias and does not meet the exclusion criterias);

• Evidence of active lupus nephritis exists, and the investigator assesses that it is necessary to receive glucocorticoid combined with MMF treatment. Active lupus nephritis must meet the following two criterias:

• a) Proteinuria:

• a) At screening: 24h-UPCR ≥ 1g/g or FMV-UPCR ≥ 1g/g or FMV-UACR ≥ 0.5g/g; b) Before randomization: 24h-UPCR ≥ 1g/g (central laboratory); b) At screening: SLEDAI-2000 ≥ 8;

• First onset or recurrence of lupus nephritis (for subjects who have received MMF treatment previously and have experienced recurrence, the investigator and the sponsor jointly assess the benefit based on the study's medication regimen to determine whether they can be enrolled);

• Female subjects with reproductive capacity \[excluding those who have undergone surgical sterilization (hysterectomy, bilateral tubal ligation, bilateral oophorectomy) at least 6 weeks prior to screening or who are postmenopausal (defined as having no menstruation for 12 months, with no other medical cause)\]; a negative pregnancy test must be confirmed during the screening period. The subject must agree not to attempt pregnancy and not to donate oocytes from the date of signing the informed consent form until at least 30 days after the last administration of investigational product, and must use effective contraception; male subjects must agree not to donate sperm for at least 90 days from the date of signing the informed consent form until at least 90 days after the last administration of investigational product, and must use highly effective contraception with their female partners (see Appendix 3).