Objective:To study the effects of Longji Xiaozhong Ointment with external application on the pathology of synovial tissue and expressions of related inflammatory factors in rabbit model of knee osteoarthritis,which based on the experience of Yu Zizhen,a famous Chinese medical physician of traumatology in Guang style. Methods60 male New Zealand white rabbits were randomly divided into the blank group,model group,Longji Xiaozhong Ointment group(treatment group)and diclofenac diethylamine group(control group). The model was established in the groups except the blank group,and then the treatment group and control group were treated with Longji Xiaozhong Ointment and diclofenac diethylamine by external application respectively. After administration for 2 weeks,the animal behavior were evaluated by modified Lequesne MG scores,and the rabbits were sacrificed. The synovial tissue of knee joint was collected,the histopathological changes were observed and the expressions of IL-1,IL-6,LT,TNF-α and MMP-3 were detected by ELISA.  Results:①Compared with the model group,the activities of rabbits with papain-induced knee osteoarthritis were improved in the treatment group and control group(P<0.05). ②Compared with the model group,the expressions of MMP-3 and IL-1 in the synovial tissue of rabbits with knee osteoarthritis were decreased in the treatment group and control group(P＜0.05,P＜0.01),and there were no statistically significant differences between the treatment group and control group(P>0.05). ③In histopathology,compared with the model group,the local synovitis was improved in the treatment group and control group(P＜0.05).  Conclusion:Longji Xiaozhong Ointment can improve the activity and pain of rabbits with knee osteoarthritis. It may be associated with the inhibition of synovial hyperplasia,reduction of synovial fluid production and expression regulation of related inflammatory cytokines.