Ulcerative colitis(UC) incidence is rising globally， and has become a serious health problem in Asia. Noni (Morinda citrifolia L.) ， a kind of medicinal and edible plant， is rich in active substances. Studies have shown that noni fruit has a variety of beneficial health functions such as anti-inflammatory， antibacterial and lowering blood lipids. In this study， mice were divided into three groups: control group(C)， model group(M)， and naturally fermented noni juice (FNJ) treated group (N). Groups M and N were gavaged with dextran sulfate sodium (DSS) to induce colitis. One week later， mice in group N were gavaged with FNJ. After two weeks， they were killed and related indicators were measured. The results showed that the disease activity index of mice in group N was significantly reduced， and the histopathological changes of colon were alleviated. Meanwhile， serum pro-inflammatory cytokines in FNJ-treated mice were also modulated to normal levels. Compared with the M group， FNJ can also regulate the composition of the intestinal microbiota of mice with colitis， with the relative abundance of Firmicutes reducing and that of Bacteroides increasing. This research provides a scientific basis for developing the nutritional function and medicinal value of FNJ， and supplies new ideas for the intestinal homeostasis and treatment of colitis.