This study is intended to evaluate the efficacy and safety of Iguratimod alone or Iguratimod in combination with Methotrexate (MTX) versus Methotrexate alone in patients with Rheumatoid Arthritis (RA).

Inclusion Criteria:

• Subjects with a diagnosis of RA according to the diagnostic criteria of the American College of Rheumatology (ACR) (revised in 1987)
• Rheumatoid Arthritis for 3 months to 2 years from the time of the initial diagnosis
• Subjects have active RA at the time of screening
• Subjects are naive to MTX or RA related biologics
• Written informed consent

Exclusion Criteria:

• Preceding treatment with DMARDs, immunosuppressants (cyclophosphamide, cyclosporine, azathioprine, etc.), or Tripterygium within 4 weeks prior to study entry
• Chest x-ray abnormalities, such as tuberculosis, interstitial pulmonary fibrosis, etc.
• ALT >1.5×ULN, AST >1.5×ULN, Cr >135umol/L
• WBC<4×109/L，HGB<85g/L，PLT<100×109/L
• Subjects with serious cardiovascular, renal, hematologic or endocrine diseases
• Pregnant or lactating women
• Allergic to any of the study drugs
• History of alcoholism
• Subjects with mental illness
• Subjects receiving live vaccines recently
• Subjects participating in other clinical study within 3 months prior to study entry