Abstract：Objective：To observe the effect of Yiqi Jiedu prescription combined with mesalazine enteric- coated tablets on the ability of scavenging oxygen free radicals and the expression of heat shock protein 70 (HSP70) in patients with ulcerative colitis. Methods： A total of 100 cases of patients with ulcerative colitis were selected and divided into the observation group and the control group according to the random number table method，50 cases in each group. The control group was treated with mesalazine enteric-coated tablets，and the observation group was additionally treated with Yiqi Jiedu prescription based on the treatment of the control group. The clinical effect in the two groups was compared. Before and after treatment， Chinese medicine syndrome scores were counted； the levels of superoxide dismutase(SOD)， glutathione peroxidase(GSH- Px)， lipid peroxide(LPO)， HSP70， interleukin- 17(IL- 17) and interleukin- 33(IL- 33) were detected. Results：The total effective rate was 94.00% in the observation group，higher than that of 80.00% in the control group，the difference being significant(P＜0.05). Before treatment，there was no significant difference being found in the comparison of Chinese medicine syndrome scores between the two groups(P＞0.05). After treatment，Chinese medicine syndrome scores in the two groups were decreased when compared with those before treatment，and the score in the observation group was lower than that in the control group， differences being significant(P＜0.05). Before treatment， there was no significant difference being found in the comparison of the levels of SOD，GSH-Px，LPO，HSP70，IL-17 and IL-33 between the two groups(P＞0.05). After treatment，the levels of SOD，GSH-Px and HSP70 in the two groups were higher than those before treatment，and the levels of LPO，IL-17 and IL-33 were lower；the levels of SOD，GSH-Px and HSP70 in the observation group were higher than those in the control group，and the levels of LPO，IL-17 and IL-33 were lower，differences being significant(P＜0.05). Conclusion：The application of Yiqi Jiedu prescription combined with mesalazine enteric-coated tablets for ulcerative colitis can scavenge oxygen free radicals，regulate the expression levels of inflammatory factors and HSP70， and improve the clinical effect.