Rheumatoid arthritis (RA) is an autoimmune disease involving multiple joints, and currently it still leads to high disability rate of the joints and high mortality. Early diagnosis and treatment can effectively reduce joint deformities. The recently discovered anti-citrullinated peptide antibodies(ACPA) can be detected before damage to the joints occurs. Compared with classical rheumatoid factor (RF) ACPA has higher specificity and similar sensitivity in diagnosing RA. Some studies have showned that anti-cyclic citrullinated peptide antibodies play an important role in the early diagnosis of RA and prediction of prognosis; epidemiological evidences also show that ACPA plays an important role on the pathogenesis of RA.