BACKGROUND: Guizhi Shaoyao Zhimu decoction (GSZD) is a recognised herbal formula that has demonstrated efficacy in the treatment of rheumatoid arthritis (RA). Despite its recognised clinical benefits and widespread use, the precise mechanisms by which this decoction exerts its therapeutic effects are not fully understood. PURPOSE: To determine the impact of GSZD on collagen-induced arthritis (CIA) mice and MH7A cells and to explore the molecular mechanisms through which GSZD operates in RA. METHODS: The in vivo effects of GSZD were evaluated in a CIA model. Network pharmacology and bioinformatics approaches were employed to identify GSZD targets. Protein expression was measured by western blotting. Matrix metalloproteinases (MMPs) expression was detected using ELISA and quantitative RT-PCR. Cell migration and invasion were determined using the Boyden chamber assay. RESULTS: The arthritis score was significantly lowered by GSZD, which also alleviated joint swelling and bone damage, reduced the pathological score, and lowered the serum levels of MMPs in CIA mice. From a mechanistic perspective, we discovered that SLPI serves as a novel target gene of GSZD in MH7A cells. The findings indicated that GSZD treatment significantly suppressed the expression of SLPI, as well as the PI3K/AKT/NF-κB signalling pathway. Additionally, GSZD treatment decreased both the migration and invasion of MH7A cells, as well as MMPs expression. Further investigations of molecular mechanisms revealed that GSZD effectively inhibited SLPI expression and PI3K/AKT/NF-κB pathway activity in TNF-α-stimulated MH7A cells. CONCLUSION: The findings indicate that GSZD markedly reduced the severity of arthritis in CIA mice and restricted the migration, invasion, and expression of MMPs in MH7A cells by interfering with the SLPI and PI3K/AKT/NF-κB signalling pathways. Our research further elucidated the underlying mechanism by which GSZD exerts its therapeutic effects in the treatment of RA and showed for the first time that SLPI could serve as a novel therapeutic target for RA, offering potential avenues for more effective treatment strategies.