Based on the inflammatory bowel disease （IBD） experimental model in dietary fiber in seaweed, we summarized its function in protecting intestinal mucosal barrier and host immune system, and emphasized its direct mechanism of inhibiting immune cell infiltration, regulating oxidative stress level, protecting antioxidant defense system, regulating intestinal tight junction protein and balancing inflammatory factors level. The indirect mechanism of intestinal microbiota mediated Short chain fatty acids （SCFA） targeting IBD protection was also discussed, and the research direction of dietary fiber in seaweed in the improvement mechanism of IBD and other intestinal diseases was proposed.