Abstract: Shiwei-Ruxiang-capsule (SWRXC) is a classic formulation widely used in the treatment of rheumatoid arthritis (RA). The study used liquid chromatography-tandem mass spectrometry (LC-MS/MS) serum untargeted metabolomics and high-throughput 16S rRNA gene sequencing association analysis to elucidate the mechanism of action of SWRXC for the treatment of Freund's complete adjuvant-induced RA. The results showed that SWRXC significantly improved symptoms and reduced serum cytokine levels in RA rats. Based on LC-MS/MS technology, metabolomics identified tryptophan metabolism, nucleotide metabolism and purine metabolism as the most relevant pathways for treatment. In addition, 16S rRNA sequencing results showed that SWRXC could ameliorate RA-induced intestinal microbial oncogenesis in rats. In conclusion, SWRXC can improve the morphology and structure of RA joint tissues, reduce serum factor levels, and may play a role in improving RA by modulating related metabolic pathways such as tryptophan metabolism, nucleotide metabolism and purine metabolism, and altering the composition of intestinal flora. Animal protocols were approved by the Animal Ethics Committee of Qinghai Normal University (No. 2021041203).