To demonstrate that the treatment effect in lupus nephritis of MZR is non-inferior to that of standard therapy CTX through analyzing overall remission rate after treatment.

Inclusion Criteria:

• Patient has been diagnosed with SLE according to American College of Rheumatology (ACR) criteria in 1997;
• Patient who has had a kidney biopsy within 365 days prior to screening which was confirmed as class III, III+V, IV, IV+V, or V according to the pathologic classification of International Society of Nephrology/Renal Pathology Society (ISN/RPS) in 2003;
• Patient with 24hr-urine protein ≥ 1.0g;
• SLE-DAI > 8 ;
• Male or female patient between 18 and 70 years (inclusive) at informed consent obtained date;
• Patient with body weight between 40kg and 80kg (inclusive) at screening;
• Patients who sign the informed consent form;

Exclusion Criteria:

• Patient who had history of allergy to any investigational product (MZR, CTX) or hormone;
• Patient who had received accumulated dosage of CTX >3g within one year prior to screening.
• Patient who had received immunosuppressant or Chinese traditional medicine with immunosuppressive effect within 30 days prior to screening;
• Patient who had received prednisone>1.0mg/kg/day or equivalent dose of other oral glucocorticoid therapies within 30 days prior to screening;
• Patient who received other investigational drugs within 30 days prior to screening;
• Patient who have received plasma exchange therapy or immunoadsorption therapy within 30 days prior to screening;
• Patient who require pentostatin or live vaccine (not including flu vaccine);
• Patient who is undergoing renal replacement therapy;
• Patient who received kidney transplantation;
• Patient with malignancy;
• Patient with severe hypertension (SBP > 160mmHg or DBP > 100mmHg) which has not been effectively controlled;
• Patient with white blood cell count <3×109/L /L(=3.0 GI/L);
• Patient with SCr > 176.8μmol/L;
• Patient who has a value that is > 3 times of the upper limit of normal range for AST or ALT;
• Patient with hepatitis B, hepatitis C or HIV infection;
• Patient with other serious infections;
• Patient who is unsuitable for participating in this study in the opinion of investigators ( e.g. uncontrolled diabetes, central nervous system lupus , lupus encephalopathy, active psychosis,osteonecrosis of the femoral head, fulminant hepatitis, peptic ulcer, etc.);
• Female patient who is pregnant, currently breast feeding or willing to become pregnant;
• Patient with any other diseases that would affect the evaluation of efficacy or safety.