To evaluate the therapy efficacy and safety of external application of Chinese medicinal in treatment of mild-to-moderate knee joint osteoarthritis by the WOMAC and VAS scores. Methods:A total of 72 mild-to-moderate knee joint osteoarthritis patients were selected and randomly divided to two groups：external application of Chinese medicinal group(n=36) and the western medicine group(n=36). External application of Chinese medicinal group was given external application of Chinese medicinal on their ashi point， 48 hours each time， the medicinal was changed every 2 or 3 days， twice per week; the western medicine group patients took glucosamine sulfate capsules orally every day， two pieces each time and three times each day. The two groups were treated for four weeks. The WOMAIC and the VAS scores were used to evaluate the efficacy before treatment， 2 weeks after treatment and 1 month after treatment. The VAS pain score was used to assess efficacy of 3 months after treatment as the long-term outcome. Results:During the treatment， 2 cases fell off in external application of Chinese medicinal group. No one fell off in oral drug group. There were significant differences (P<0.05) in VAS pain score in both groups compared with the statistics before the treatment， 2 weeks， 1 months and 3 months after the treatment. There were also significant differences (P<0.05) in WOMAC scores in both two groups compared with the statistics before the treatment， 2 weeks and 1 month after treatment. There were significant differences in VAS pain score (P<0.05) after two weeks’ treatment between the two groups， but no differences in WOMAC scores. No significant differences were shown in VAS pain score and WOMAC scores after 1 month’s treatment in two groups. One case in external application Chinese medicinal group showed mild allergy (adverse effect rates=3%). Three cases experienced gastrointestinal tract reaction in western medicine (adverse effect rates=8%). Conclusion:External application of Chinese medicinal is a safe and effective treatment with certain long-term effect.