Objective To investigate the diagnosis value of soluble B7-H4(sB7-H4) in rheumatoid arthritis (RA) .Methods By using the ELISA sandwich method ,the serum levels of soluble B7-H4 ,anti-cyclic citrullinated peptide(anti-CCP) antibody and glu-cose 6-phosphate isomerase(GPI) were detected in 67 cases of RA ,72 cases of osteoarthritis(OA) and 75 cases of healthy people . The immunoturbidimetric method was adopted to determine the serum rheumatoid factor (RF) .Then the diagnostic value of sB7-H4 in RA was compared and analyzed .Results The serum level of soluble B7-H4 in the RA group was significantly higher than that in the control group and the OA group with statistically significant difference between them (P<0 .01) .The sensitivity of sB7-H4 in diagnosing RA was higher than that of RF ,anti-CCP antibody and GPI ,but the specificity was lower than that of anti-CCP antibody and GPI .There was better correlation between sB7-H4 with RF and anti-CCP antibody .The combination detecting of sB7-H4 ,RF , anti-CCP antibody and GPI could increase the diagnostic rate of RA .Conclusion B7-H4 has better clinical application prospects in diagnosing RA .