To explore the effect of Tongluo Zhitong Decoction on the proliferation of knee osteoarthritis (KOA) synovial fibroblasts. Methods:The abandoned synovial tissues were taken from patients who had knee replacement surgery in the hospital. The tissues were primarily cultured after digestion in I type collagenase. Three to four generation fibroblasts were taken for high-medium-low concentration intervention. The proliferation of KOA synovial cells was detected by 4-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) and the cell morphology was observed under the inverted microscope. Results:Comparisons between the drug groups and comparisons between the drug groups and the control group,the difference was statistically significant (P<0.05). MTT assay showed that s the light OD number of KOA synovial cells became greatest in the wavelength of 490 nm when Tongluo Zhitong Decoction concentration decreased. The inhibition rates of high-medium concentration groups were positive. With the increase of the concentration,the inhibition rate increased and the inhibition rate of the low concentration group was negative. With the concentration decreased,the inhibition rate reduced. Conclusion:The medium-high concentrated Tongluo Zhitong Decoction may inhibit the proliferation of synovial cells,while low concentrated Tongluo Zhitong Decoction may promote the proliferation of synovial cells.