Abstract：Objective：To observe the curative effect of modified Shaoyao tang for ulcerative colitis(UC) in active stage and its effect on pathological changes of colon. Methods：A total of 50 cases of UC patients in active stage were divided into the control group and the treatment group according to simple randomization method，with 25 cases in each group. The control group was treated with mesalazine enteric- coated tablets，and the treatment group was additionally treated with modified Shaoyao tang based on the treatment of the control group. After one course of treatment， the clinical effects in the two groups were evaluated. Before and after treatment，Chinese medicine syndrome scores，levels of inflammatory factors in serum，colonoscopy and pathological changes of colon in the two groups were compared. Results：The total effective rate was 96.00% in the treatment group，higher than that of 76.00% in the control group(P＜0.05). After treatment，scores of Chinese medicine syndromes， colonoscopy and pathological changes of colon as well as levels of interleukin- 6(IL- 6)， interleukin- 8(IL- 8) and tumor necrosis factor- α(TNF- α) in serum in the two groups were decreased when compared with those before treatment(P＜0.05)；scores of Chinese medicine syndromes，colonoscopy and pathological changes of colon as well as levels of IL-6，IL-8 and TNF-α in serum in the treatment group were lower than those in the control group(P＜0.05). Conclusion：Modified Shaoyao tang has a definite curative effect in treating UC in active stage，which can effectively relieve clinical symptoms， improve colonoscopy results and pathological characteristics of colon， and relieve inflammatory responses.