Abstract: Objective: To study arthroscopic synovectomy and debridement of knee Joint osteoarthritis.Methods: Arthroscopic synovectomy and debridement were performed in one hundred and fifty two knees in 93 patients with ostoarthritis.Results: The main pathological change,of osteoarthritis were synovitis, degeneration of ostechondral tissue and osteophyma, After debridement and irrigation joint pain and swelling subsided in most of patients and the range of motion much improved. Conclusion: Arthroscopic synovectomy and debridement for osteoarthritis of knee joint may improve the function, stop pain and delay the developing process of osteoarthritis. Thus, it is a good method for treatment of osteoarthritis.