Objective:This study aims to investigate the pathogenesis of ulcerative colitis (UC). The changes of IL-6 and STAT3 protein in colon of UC model rats were observed after intervention with STAT3 pathway inhibitor or/and by “Xianglian Pill”. MethodsOne hundred male Wistar rats were randomly divided into 5 groups:control group, model group, Chinese medicine group(“Xianglian Pill”), inhibitor group, and Chinese medicine plus inhibitor group. The experiment was performed in rats of UC induced by TNBS enema, and then AG-490 and “Xianglian Pill” were administered to rats by intraperitoneal injection and gavage respectively. Colonic mucosal tissue were observed and evaluated by light and electron microscopy. The expressions of IL-6 and STAT3 protein were tested by western blot.  Results:There were many ulcers in the colon of UC model rats, the pathological changes in colonic mucosa such as inflammation, congestion and edema were observed in the colon of UC model rats by naked eye and microscope. The expressions of IL-6 protein and STAT3 protein were increased in the colon of UC model rats, while decreased in Chinese medicine group, inhibitor group and Chinese medicine plus inhibitor group.  Conclusion: The abnormal expression of related factors in IL-6/STAT3 pathway is the molecular basis for the occurrence of ulcerative colitis. “Xianglian Pill” can regulate the IL-6/STAT3 pathway to inhibit activation of STAT3 in UC intestinal mucosa, and promote the apoptosis of inflammatory cells.