By detecting expression of interleukin (IL)-17A, IL-10 and interferon-γ (IFN-γ) in serum of inflammatory bowel disease (IBD) patients, this study aims to analyze the effects of these factors on the pathogenesis of IBD. According to illness status, selected patients were divided into Crohns disease (CD) group (28 patients), ulcerative colitis (UC) group (74 patients) and normal control group (36 patients); enzymelinked immunosorbent assay (ELISA) was used to detect IL-17A, IL-10 and IFN-γ levels in serum; immunohistochemical assay was used to detect local IL-17A expression in the colonic mucosa of each group. Clinical results showed that IL-17A content of the UC group and CD group was significantly higher than that of the normal control group (p less than 0.05); IL-17A content of the CD group was higher than that of the UC group (p>0.05). The UC group had the highest IL-10 content, and the difference between the UC group and other two groups had statistical significance (p less than 0.05); the difference of IL-10 content between UC group and normal control group had no statistical significance (p>0.05). There was no significant difference of IFN-γ level between the CD group and the UC group and normal control group (p>0.05), and no significant difference of IFN-γ level was shown between the CD group and the UC group (p>0.05). Both the CD and UC groups showed IL-17A positive staining in cytoplasm of lymphocyte, however no positive staining was found in any layer of intestinal mucosa of the normal control group. IL-17A was locally expressed in the colon of IBD patients in remission; furthermore, it also had high expression in serum; thus, there still existed high expression of pro-inflammatory factor, which might be related to relapse of IBD. Therefore, prevention of IL-17A may become a feasible therapy for IBD in the future.