To investigate the effect of Gubi Decoction on matrix metalloproteinase-13 and transforming growth factor β1 in knee osteoarthritis rats.Methods:A total of 40 healthy SD rats were selected to establish knee osteoarthritis model,and randomly divided into a control group and a treatment group,with 20 rats in each group.The control group was not treated after the model making operation,and the treatment group was given fumigating and steaming treatment of Gubi Decoction for 4 weeks.After treatment,the pain threshold,the diameter of the knee joint and the activity of the knee joint were compared.The expression of matrix metalloproteinase-13(MMP-13)and transforming growth factor β1(TGF-β1)in articular cartilage of rats in each group was detected by immunohistochemistry.Results:After treatment,the pain threshold,the diameter of knee joint and the range of motion of knee joint in the treatment group were significantly improved,compared with the control group(P<0.05); the expression level of MMP-13 in the treatment group was significantly lower than that in the control group(P<0.05); the expression level of TGF-β1 in the treatment group was significantly higher than that in the control group(P<0.05).Conclusion:Gubi Decoction can improve the pain of knee osteoarthritis,reduce the expression of MMP-13 in cartilage,delay the development of osteoarthritis,and obviously up regulate the expression of TGF-β1 to promote cartilage repair.