AIM: Yi Qi Yang Yin Decoction (YQYY) has been used to treat patients with rheumatoid arthritis (RA) and achieved good results in clinical applications, but the mechanism still needs to be explored. The purpose was to investigate the mechanism of YQYY in rats with collagen-induced arthritis. METHODS: The possible treatment target and signaling pathway were predicted by bioinformatics and network pharmacology analysis. Elisa,quantitative real-time polymerase chain reaction, and Western Blot were used to verify the mechanism of YQYY in treating RA. RESULTS: FABP4, MMP9 and PTGS2 were the most common predicational therapeutic targets. The results of pathology and CT showed that YQYY could improve ankle swelling, synovitis and bone erosion in CIA rats. Compared with the model group, YQYY or YQYY+MTX can significantly reduce the secretion of CRP, TNF-α, IL-1β and FABP4 in serum of CIA rats (P<0.05 or P<0.01), meanwhile, reduce the mRNA of FABP4, IKKα and p65 in synovial tissue (P<0.01), PPARγ was increased (P<0.01). YQYY could significantly reduce the expression of FABP4, IKKα and pp65 proteins in synovium, and suppress the activate of NF - κB signaling pathway. CONCLUSION: FABP4, MMP9 and PTGS2 may be the targets of YQYY decoction for RA treatment. YQYY can relieve joint symptoms in CIA rats, and regulate inflammation by inhibiting FABP4 / PPARγ/NF - κB signaling pathway, playing a role in the treatment of RA. The effect of YQYY combined with MTX was more prominent. This provided experimental evidence for the efficacy of YQYY decoction in clinical practice.