Objective To observe the degree of joint flexion and extension of elbow and knee joints of moderate skeletal fluorosis patients before and after treatment and to assess the effects of Gun's MaQian decoction in treating moderate skeletal fluorosis. Methods 54 moderate skeletal fluorosis patients were randomly recruited into a treatment group and a control group. The treatment group was treated with Gun's MaQian decoction initially, and changed to be treated with GuKangNing capsule after 8 weeks' treatment. The control group was treated with placebo at first, and also changed to be treated with GuKangNing capsule after 8 weeks. Results Joint flexion and extension of elbow was improved greatly in both groups after the treatment, while the treatment group showing better effects than the control group (P<0.05). The improvement of joint flexion and extension of knee had not showed a statistical significance after the treatment. A 24 weeks follow-up to the joint flexion and extension of both elbow and knee revealed obvious improvement and the difference between the two groups were significance (P<0.05). Conclusion Gun's MaQian decoction can improve the flexion and extension of elbow and knee in moderate skeletal fluorosis patients.