Rheumatoid arthritis (RA) is a chronic multisystemic disease of unknown cause, a systemic disease characterized by non-infectious inflammation of joints and periarticular tissues. Although there are many different systemic manifestations, rheumatoid lesions are characterized by persistent synovitis, usually involving symmetrical peripheral joints. Synovitis can cause destruction of articular cartilage and bone erosion, which in turn can lead to joint deformity and become the hallmark of the disease. The course of rheumatoid disease varies from mild lesions in a few joints of short duration in some patients to severe progressive polyarthritis with significant joint deformities in others. Most patients present with something in between. Rheumatoid arthritis, a specific rheumatic disease that was reported 2000 years ago, continues to ravage the world with its high incidence, long course, and late stage disability in most patients. The prevalence of rheumatoid arthritis is about 1.4% of the total population worldwide, and the prevalence in China is about 0.3%, mostly between the ages of 30 and 50, and about 3-4 times higher in women than in men.