Abstract: Objective: To research the therapeutic effects and mechanisms of ligustilide (Lig) in improving dextran sodium sulfate (DSS)-induced ulcerative colitis (UC) in mice. Methods: Intervention of Lig was delivered in sixty male SPF C57 BL/6 mice and the mice were differentiated in six groups according to the dose of Lig as: Control group, DSS group, positive control group (treated with sulfasalazine, SASP), low-dose Lig group, medium-dose Lig group, and high-dose Lig group. The UC in DSS mice was induced by a 3% DSS solution through oral administration for 7 days, in the meanwhile, the low, medium, and high-dose Lig groups received gavage feeding of Lig and oral administration of 3% DSS solution. Before and after the intervention, the body weight ,colon length, and the disease activity index (DAI) score were collected for assessment of UC. Furthermore, the expression levels of TLR4/NF-κB proteins in colon and serum TNF-α, IL-6, and IL-1β were quantitatively measured using enzyme-linked immunosorbent (ELISA) assays. Additionally, histological examination was performed to investigate the effects and mechanisms of Lig in improving UC in mice by hematoxylin-eosin staining. Results: Compared to the control group, significantly reduced body weight, shorter colon length, increased DAI score, extensive inflammatory infiltration in the intestinal tissue, and significantly elevated expression levels of TNF-α, IL-6, and IL-1β in the colon (P<0.05) were observed in the DSS group. Compared to the DSS group, significant suppression of the TLR4/NF-κB signaling pathway in the intestinal tissue, serum TNF-α, IL-6, and IL-1β expression (P<0.05) were observed in the medium and high-dose Lig groups, which indicated a significant improvement in intestinal damage. Conclusion: Lig is able to effectively improve DSS-induced UC in mice. Moreover, the results showed that the mechanism of Lig improving DSS-induced UC was possibly involved with the inhibition of the NF-κB signaling pathway.