Abstract: Objective: To observe the clinical effect of Qingre Badu plaster for knee osteoarthritis(KOA) of damp- heat accumulation type. Methods: The KOA patients who met the inclusion criteria were randomly divided into four groups, namely the manual massage group(Group A),the Qingre Badu plaster and manual massage group(Group B),the Qingre Badu plaster group(Group C) and the control group with voltaren emulgel(Group D), 23, 25, 27 and 24 cases in each group respectively. Finally,a total of 99 patients completed the study. Before and after treatment,the scores of Western Ontario and Mcmaster Universities Osteoarthritis Index(WOMAC) and Visual Analogue Scale(VAS) were observed; tumor necrosis factor-α(TNF-α),interleukin-1β(IL-1β) and matrix metalloproteinase-1(MMP-1) in synovial fluid were detected by Enzyme Linked Immunosorbent Assay(ELISA). Results:The scores of WOMAC and VAS in Group B and Group C were better than those in Group A and Group D,differences being significant(P<0.05). The detection of TNF-α,IL-1β and MMP-1 showed that the levels in Group B, C and D were better than those in Group A, differences being significant(P<0.05). The total effective rate was 88.00% in Group B and 85.19% in Group C,higher than those of 73.91% in Group A and 79.17% in Group D,differences being significant(P<0.05). During treatment,there was no response to massage manipulation and no adverse reaction to drugs in the four groups. Conclusion: The external application of Qingre Badu plaster, with Radix Stephaniae Tetrandrae as the chief medicinal, has definite clinical effect for KOA patients of damp- heat accumulation type, and can improve clinical uncomfortable symptoms,reduce inflammatory responses in knee joint fluid with high safety.