Abstract: Objective: The preventive effects of Kuding tea crude polyphenol ( KTCP) on ulcerative colitis were determined through the DSS ( Dextran sulfate sodium salt) -induced ulcerative colitis ( UC) animal model in this study.Method: Experiment kits were used for the mice serum determination, meanwhile, the mRNA of mice colon tissue were determined by RT-PCR assay.Results: The animal experiment results showed that KTCP could control the UC caused mice body weight reduction and DAI ( disease activity index) raise.Meantime, KTCP also could control the UC caused colon length shortening and colon ratio of weight/colon length reduction.After dissection, the serum and tissue of mice were experimentalized, it was observed that KTCP could increase the content of SOD ( superoxide dismutase) in serum, decrease the cytokine levels of IL-6 ( interleukin-6) , IL-12 ( interleukin-12) and TNF-α ( tumor necrosis factor alpha) .And it was also observed that KTCP could reduce the MPO ( myeloperoxidase) , MDA ( malondialdehyde) contents and raise the GSH ( glutathione) content in colon tissues. RT-PCR experiment results showed that KTCP could decrease the TNF-α, IL-1β, IL-6, IL-8 and CXCR2 mRNA in colon tissues compared to the control group mice. Meanwhile high concentration of KTCP could make the experiment index close to the normal group mice, and showed the better activities.Conclusion: As can be seen, KTCP had a good preventive effects of UC.