Objective： To explore the significance of synovial fluid（SF）anti-cyclic citrullinated peptide (CCP) antibodies  and anti-mutated citrullinated vimentin (MCV) antibodies in the diagnosis of serum negative rheumatoid arthritis (SNRA). Methods: Enzyme linked immunosorbent assay (ELISA) method was apllied in the detection of two groups of patients with knee joint fluid resistance against CCP antibody and antibody of MCV, the experimental group to SNRA patients, a total of 29 cases, and the control for patients with osteoarthritis (OA), a total of 28 cases, and clinical manifestations and laboratory parameters of the two groups were collected. Results: The positive rate of synovial fluid anti-CCP was 34.5% in the SNRA patients, which was significantly higher than 10.7% in the control patients（χ2=4.571, P＜0.05）. The positive rate of synovial fluid anti-MCV was 20.7% in the SNRA patients, which was significantly higher than 7.1% in the control patients（χ2=2.167, P＞0.05）. The SNRA patients of SF anti-CCP and anti-MCV positive had no significant difference from the SNRA patients of SF anti-CCP and anti-MCV negative in age, course and morning stiffness. The levels of erythrocyte sedimentation rate (ESR) , C-reactive protein(CRP) and DAS28 scores in the SF anti-CCP positive patients were higher than those of the SF anti-CCP negative patients. The levels of ESR, CRP and DAS28 scores in the SF anti-MCV positive patients were higher than those of the SF anti-MCV negative patients, (all P<0.01). SF anti-CCP had correlation with ESR, CRP(r=0.567, P<0.01; r=0.664, P<0.01). SF anti-MCV had correlation with ESR, CRP(r=0.344, P<0.01; r=0.749, P<0.01). Conclusion: SF anti-CCP and anti-MCV are helpful for the diagnosis of SNRA and judgement of SNRA activity.