Objective To investigate the significance of serum interleukin-1β,interleukin-2,interleukin-6,TNF-α,erythrocyte sedimentation rate(ESR),c-reactive protein(CRP),IgA,IgG and IgM in patients with ankylosing spondylitis(AS),and to analyze their relationship with the Bath ankylosing spondylitis disease activity index (BASDAI). Methods Participants of this study included 45 AS patients(patient group)and 30 healthy subjects (control group).The patient group was further divided into an active subgroup and an inactive subgroup based on the disease activity assessed by using BASDAI.Then serum levels of IL-1β,IL-2,IL-6,TNF-α,ESR,CRP,IgA,IgC and IgM were tested in all the subjects,and the values were compared between different groups.In addition,the relationship between various parameters and those with BASDAI were also evaluated. Results The serum levels of ESR,CRP,IgA,lgM,IgG,IL-1β,IL-2,IL-6 and TNF-α in patients with AS were significantly higher than those in the healthy controls(P<0.05).The serum level of CRP,IL-2 and IL-6 were significantly different between the active and inactive subgroups(P<0.05).There was a positive correlation between CRP and IL-6,IL-6 and IL-2,as well as IgA and IgG levels.The IL-2,IL-6 and CRP levels were positive correlated with BASDAI.Conclusion It was suggested that the serum levels of IL-2,IL-6 and CRP can be used to assess the disease activity in patients with AS.