This study investigated the efficacy and safety of modified Qinbai Decoction in the treatment of ulcerative colitis.Methods:A total of 104 patients with ulcerative colitis who were admitted to the Second Affiliated Hospital of Hunan University of Chinese Medicine the from January 2018 to July 2020，were selected and randomized into the control group and observation group with the random number table method，52 in either group.The control group was treated with mesalazine and the observation group with mesalazine and modified Qinbai Decoction.The efficacy in the two groups was compared.Results:The effective rate in the observation group(96.15%) was higher than in the control group(84.62%)(P<0.05).Before treatment，the TCM syndrome score(diarrhea and abdominal pain，abdominal distension and bleeding stools，tenesmus，and poor appetite and fatigue)，Baron score for intestinal mucosal changes，Geboes score for histological severity，and the levels of interleukin-10(IL-10) and tumor necrosis factor α(TNF-α) in two groups were insignificantly different(P>0.05).After treatment，the indexes in either group were improved and the improvement in the observation group was better than that in the control group(P<0.05).The occurrence of adverse reactions was low in control group(1.92%) and observation group(0.00%) with insignificant difference(P>0.05).The recurrence rate in 6 months in observation group(0.00%) was lower than that in control group(7.69%)(P<0.05).Conclusion:Modified Qinbai Decoction is effective and safe in the treatment of ulcerative colitis.