Objective:To observe the effects of Zhiyuanfang inhibiting platelets amplified inflammation and proliferation of synovial cells in the rheumatoid arthritis（RA） rats.Method:Normal cultured RSC364 cells were divided into normal control group

RA model group

activated platelet intervention group and Zhiyuanfang group.The different concentrations of tumor necrosis factor-α（TNF-α） were used to induce RA rat cell models

stimulate platelets activating by bovine type II collagen

and interfere platelet intervention group with Zhiyuanfang containing serum.The expression of interleukin-6（IL-6）

interleukin-8（IL-8） and P-selecting were assayed respectively by enzyme-linked immunosorbnent assay（ELISA）

and the proliferation of RSC364 cells were determined by MTT colorimetric assay.Result:①The expression of P-selecting was at peak when platelets were activated by bovine type II collagen for 5 h.②the expression of IL-6 and IL-8 on synovial cells in RA model group was increased

which was compared with the same concentration of normal group showed a significant difference（P<0.05）;the rate of RSC364 cells proliferation was also higher than normal group（P<0.05）in a dose-dependent manner.③Compared with RA model group

the expression of IL-6 and IL-8 on synovial cells in platelets intervention group was significantly increased（P<0.05

P<0.01）

and the rate of synovial cells proliferation was also higher（P<0.05）.④ Compared with platelets intervention group

the expression of IL-6 and IL-8 on synovial cells in Zhiyuanfang group was significantly reduced（P<0.05

P<0.01）

the proliferation rate of synovial cells was declined（P<0.05）

and the expression of P-selecting was also lower.Conclusion:Activated platelets amplify the inflammation and proliferation of synoviocytes;Zhiyuanfang effectively can relieve the amplification of platelets on the inflammation and proliferation in RA rats probably by the inhibition of P-selecting expression.