Rheumatoid arthritis (RA), an inflammatory autoimmune disorder, is characterized by synovial chronic inflammation and hyperplasia, autoantibody production, cartilage and bone destruction. Oxidative stress has also been reported to be involved in RA pathogenesis. Glycine tabacina (Labill.) Benth, named Yan Dou in Chinese, has been used as a traditional herbal medicine to treat RA and joint infection in China. However, very few studies have been carried out to reveal chemical constituents and pharmacological activities of this species. Therefore, the present study aimed to investigate the anti-arthritic effect of ethanol extract of G. tabacina (GTE) in collagen-induced arthritis (CIA) animal models for the first time, and clarify the underlying mechanism(s). The results showed that oral administration of GTE (1.11, 2.22 and 4.44 g dried weight of herb per kg body weight) from day 0 to day 30 significantly ameliorated the arthritic symptoms in CIA rat model, as indicated by the reduction in paws swelling and arthritis index. X-radiographic analysis and histopathological examinations demonstrated that GTE effectively protected the bone and cartilage of joints from erosion, lesion and deformation. The efficacy of GTE treatment on CIA was comparable to that of indomethacin (positive drug). The overproduction of interleukin1β (IL-1β), IL-6 and tumor necrosis factor α (TNF-α) was remarkably inhibited in the serum of all GTE treatment groups. The restoration of serum total superoxide dismutase (T-SOD) activity and malonaldehyde (MDA) levels proved that GTE administration alleviated the oxidative stress in CIA rats. Besides, GTE treatment significantly decreased swelling volume and thickness of arthritic paw as well as serum levels of TNF-α and IL-1β in CIA mice model, further confirming its inhibitory effect on RA progression. In LPS-induced RAW264.7 macrophages, treatment with GTE (50, 100 and 200 μg/mL) significantly inhibited the expression of iNOS, production of inflammatory mediators (nitric oxide, IL-6, TNF- α) and nuclear translocation of nuclear factor kappa-B (NF-κB) p65. Taken together, GTE is a potential effective candidate for the prevention and treatment of RA, which executes anti-RA effect potentially through inhibiting oxidation and NF-κB signal pathway activation and subsequent inflammation.