Rheumatoid　arthritis　(RA)　is　a　chronic　autoimmunity　disease　which　shows　synovitis.The　activity　of　SOD　in　RA　patient　is　reduced,which　attenuated　the　ability　to　dear　free　radical.We　performed　animal　experiments　to　test　the　effect　of　the　superoxide　dismutase　(SOD)　and　the　fusion　protein　(PTD-SOD)　consisting　of　a　SOD　linked　to　a　protein　transduction　domain　(TAT)　in　RA　treatment.