Objective：To observe the clinical effect of Weifeng Guke external washing powder combined with articular cavity injection of medical chitosan for knee osteoarthritis.Methods：Divided 90 cases of patients with knee osteoarthritis into three groups randomly，30 cases in each group.The combination group was treated with Weifeng Guke external washing powder combined with articular cavity injection of medical chitosan；the external washing group simply received Weifeng Guke external washing powder；the chitosan group was solely given articular cavity injection of medical chitosan.Observed the scores of visual analogue scale(VAS)and Western Ontario and McMaster Universities Osteoarthritis Index(WOMAC)before and after treatment in the three groups，and evaluated the therapeutic effect.Results：After treatment，VAS scores in the three groups declined continuously，differences being significant(P＜0.01).The VAS score in the combination group was lower than that in the external washing group and the chitosan group respectively at the same period，differences being significant(P＜0.01).After six-week treatment，the scores of WOMAC in the three groups were improved when compared with those before treatment，differences being significant(P＜0.01).The score of WOMAC in the combination group was higher than that in the external washing group and the chitosan group respectively，differences being significant(P＜0.01).The combination group had better clinical effect than the external washing group and the chitosan group，differences being significant(P＜0.05).Conclusion：The therapy of Weifeng Guke external washing powder combined with articular cavity injection of medical chitosan for knee osteoarthritis，can effectively alleviate pain and improve knee joint function of patients，which is worthy of clinical promotion and application.