Objective · To investigate correlation of serum acute amyloid A (A-SAA) level and activity of Behcet's disease (BD).  Methods · Blood samples from patients with active BD (n=40), remission BD (n=15), Takayasu disease (TA, n=12), rheumatoid arthritis (RA, n=25), systemic lupus erythematosus (SLE, n=25) and healthy donor (HD, n=25) were collected. Serum A-SAA, ESR, and CRP levels were detected and compared among groups. The correlation between A-SAA and its downstream IL-8 or International Society for Behcet's disease (ISBD) disease activity scores was analyzed as well.  Results · Serum A-SAA level was significantly increased in the patients with active BD [(115.70±87.78) mg/L], as well as patients with RA and TA, which levels were (68.72±61.50) mg/L and (96.25±87.41) mg/L respectively, but remained unchanged in SLE patients. Moreover, serum A-SAA level was found correlated with ISBD score as well as IL-8 level.  Conclusion · A-SAA can work as a detection index for evaluating BD activity.