Rheumatoid arthritis (RA) is a chronic autoimmune inflammatory disease, and emerging evidence highlights a crucial role for the gut microbiota in its pathogenesis. Previous studies have emphasized the involvement of Lactobacillus species in modulating RA. In this study, we observed a deficiency of Lactobacillus in RA patients. Using animal models, we investigated the effects of Lactobacillus plantarum AR1074 intervention on rheumatoid and inflammatory markers in the serum and synovial joints of RA rats. Our results demonstrate that AR1074 effectively alleviates oxidative stress in RA rats. Moreover, AR1074 attenuated RA symptoms by upregulating intestinal tight junction proteins, modulating short-chain fatty acid levels, and enhancing gut microbiota diversity.