Abstract: OBJECTIVE To investigate the effect of Layers Adjusting External Application Therapy on the expression of synovial inflammatory factors and matrix metalloproteinase (MMPs) in osteoarthritis (OA). METHODS 30 New Zealand rabbits were randomly divided into normal group， control group and treatment group. OA model was induced in rabbit by unilateral posterior anterior cruciate ligament transection (ACLT). 6 weeks post-operation， the Layers Adjusting External Application Therapy were used externally; 8 weeks post-operation， the rabbits were sacrificed. The synovial membrane specimens were taken to detect the expression and content of IL-1β， MMP-1 and MMP-13 by Western Blot and Fluorogenic Quantitative PCR. RESULTS Western Blot: The content of MMP-1 and MMP-13 in the control group were significantly higher than the treatment group. The content of MMP-1 and MMP-1 in the normal group were the lowest Fluorogenic Quantitative PCR. The expression of MMP-1 and MMP-13 in the control group were the highest the expression of MMP-1 and MMP-13 in the normal group were the lowest the expression of IL-1β in the normal group was significantly lowest. There were no significantly differences in the expression of IL-1β between control group and treatment group. CONCLUSION Layers Adjusting External Application Therapy can effectively inhibit the expression of MMP-1 and MMP-13 in the Synovial Membrane， thus reduces the degradation of cartilage matrix alleviate the progression of OA. Nevertheless， further research are needed to investigate the specific target so that the mechanism of the therapy can be revealed.