This study will evaluate the efficacy, safety, pharmacokinetics(PK) ,pharmacodynamics（PD）and anti-drug antibodies（ADA） of MIL62 compared with cyclosporine in participants with primary membranous nephropathy (pMN).

Inclusion Criteria:

1. Age 18-80;
2. Diagnosis of primary membranous nephropathy (pMN) according to renal biopsy prior to or during screening;
3. Screening 24-hour urinary protein >= 5 g after best supportive care for >= 3 months prior to screening or screening Screening 24-hour urinary protein > 3.5 g after best supportive care for >= 6 months prior to screening, or Screening 24-hour urinary protein > 3.5 g with at least one high-risk factor defined by the protocol;
4. Estimated glomerular filtration rate (eGFR ) by Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) formula ≥40 mL/min/1.73 m^2;
5. If taking ACEI(Angiotensin converting enzyme inhibitors), ARB(Angiotensin receptor blocker), a stable dose within 4 weeks before screening is required;
6. Sufficient organ function;
7. Able and willing to provide written informed consent and to comply with the study protocol.

Exclusion Criteria:

1. Participants with a secondary cause of MN;
2. Cyclosporine resistance;
3. Received treatment drugs for membranous nephropathy;
4. Concomitant with other serious diseases；
5. Received live vaccination, major surgery (excluding diagnostic procedures), and participated in other clinical trials within 28 days prior to receiving the first study drug;
6. Patients who are positive for hepatitis B surface antigen (HBsAg) and/or hepatitis B core antibody (HBcAb), with HBV DNA levels above the normal range (HBsAg and/or HBcAb-positive patients require regular HBV DNA testing); patients positive for hepatitis C virus (HCV) antibodies; or patients with a positive human immunodeficiency virus (HIV) serology.
7. Participants with CD4+ T lymphocyte count < 200 cells/μL;
8. Those who have a clear history of tuberculosis or have received anti- tuberculosis treatment;
9. Participants with known history of severe allergic reactions to humanized monoclonal antibodies, MIL62, or Cyclosporine
10. Breastfeeding or pregnant women;
11. Childbearing potential and unwillingness or impossibility to comply with a scientifically acceptable birth-control method
12. Other conditions unsuitable for participation in this study determined by the Investigator.