Abstract: To investigate the pharmacodynamic effects and mechanism of Zhuling Jianpi capsule(Zhuling) on 2,4, 6-trinitrobenzene sulfonic acid (TNBS)-induced experimental colitis in rats.The experimental colitis model was established by enema with 2.5% TNBS.The rats were randomly divided into normal group,model group,Changyanning (180 mg/kg) group and Zhuling low-dose (40 mg/kg) group and Zhuling high-dose (120 mg/kg) group.After modeling,the rats were executed after 7 days of drug treatment.During this period,the disease activity status of the rats was observed,and the body weights of the rats were recorded daily.At the end of the experiment,the colonic tissues were obtained for the analysis of the expression of hematoxylin-eosin(HE) staining.The myeloperoxidase (MPO) enzyme activity,mRNA expression levels of inducible nitric oxide synthase (iNOS) and inflammatory cytokines (IL-6, IL-1β, IFN-γ, IL-10) were determined, and the levels of intestinal tight junction proteins and serum inflammatory factor levels were measured.The results showed that compared with model group, the administration of Zhuling significantly alleviated the weight loss and elevated the disease activity index (DAI) caused by TNBS, relieved the shortening, edema and pathological damage of colonic tissue, reduced inflammatory cell infiltration, destruction of crypt and loss of goblet cells, decreased the MPO enzyme activity of colonic tissue, iNOS and pro-inflammatory cytokines in colon, increased the levels of colonic tight junction protein (occludin, ZO-1), and decreased serum levels of inflammatory factors (IL-6,IL-1β).The results suggest that Zhuling administration ameliorates TNBS-induced experimental colitis in rats by decreasing the level of inflammatory factors and increasing the expression of intestinal tight junction proteins.This experiment could provide a theoretical basis for the clinical application of Zhuling.