Objective:To study the effect of mesalazine hydroxyl-propyl-β-cyclodextrin inclusion compound ( MSZ-HP-β-CD) liq-uid suppositories on ulcerative colitis ( UC) in rats. Methods:Dextran sulfate sodium was used to induce UC in rats. The marketed MSZ suppositories were applied as the positive control, and the changes in morphology and histopathology of the UC rats were observed after the treatment with MSZ-HP-β-CD liquid suppositories. Results:The results of morphology study showed that CMDI was decreased in the two MSZ preparation groups when compared with that in the model group (P<0. 01), and that in MSZ-HP-β-CD liquid supposi-tories group was the lowest (P<0. 05). The results of histopathology study showed that with the treatment of the marketed MSZ sup-positories and MSZ-HP-β-CD liquid suppositories, the ulcer and damage were improved, and the improvement in the MSZ-HP-β-CD liquid suppositories group was more significant. Conclusion: MSZ-HP-β-CD liquid suppositories exhibit better effect on UC in rats when compared with the marketed MSZ suppositories, which is worthy of further studies.