Abstract: Objective: To investigate the effects of Ginsenoside Rg1 on the proliferation, invasion and secretion of inflammatory factors of fibroblast-like synoviocytes(FLSs),so as to provide theoretical and experimental basis for the clinical treatment of rheumatoid arthritis(RA). Methods: FLSs of RA were isolated and cultured in vitro. FLSs were stimulated by tumor necrosis factor- α(TNF- α). Different concentrations of Rg1(0, 0.4, 4 and 40 mmol/L) were added in the above conditions. After 24 hours of culture,expression changes of interleukin-6(IL-6) and interleukin-1β(IL-1β) were detected by real-time fluorescence quantitative PCR(RT-PCR),Western blot and Enzyme-linked immunosorbent assay(ELISA). CCK- 8 clone formation and Transwell evaluation of cell proliferation and invasion. The effect of Rg1 on the activation of mitogen activated protein kinase/extracellular regulated protein kinase(MAPK / ERK) pathway was evaluated by Western blot. Results: At the gene and protein levels, Rg1 could inhibit the expressions of IL- 1β and IL- 6 induced by TNF- α, and limit their secretion. In addition, Rg1 can significantly inhibit the invasion and proliferation of FLSs.In mechanism, Rg1 inhibited the phosphorylation of ERK and hindered the activation of MAPK/ERK pathway. Conclusion:Rg1 inhibits the activation of MAPK/ ERK pathway in FLSs,limits cell proliferation and invasion,and prevents inflammatory factors IL-6 and IL-1β. And thus play a role in the treatment of RA.