Rheumatoid arthritis (RA) is a chronic and disabling disease. tumor necrosis factor-a(TNF-a) inhibitors have demonstrated an outstanding performance in relieving joint inflammation and retarding bone erosion involved in RA. However, there is still about one-thirds of RA patients had a poor response to TNF α inhibitors. The Investigators hope to discover prediction protein with a domestic genetic background and finally establish prediction system with Chinese characteristics.