Constipation is one of the most common gastrointestinal tract symptoms. In this study, prebiotic sesame sugar (PSC) was prepared from isomalto-oligosaccharide, konjac glucomannan and sesame, and the relieving effect of PSC on constipation induced by loperamide was explored. The results showed that PSC treatment profoundly improved the defecation function and boosted intestinal motility. Moreover, PSC repaired gastrointestinal tissue injury and inflammation induced by constipation, which confirmed the effectiveness of PSC intervention in the treatment of constipation. The mechanism of PSC improving constipation might be that PSC improved the imbalance of gastrointestinal neurotransmitters and increased the content of short-chain fatty acids in feces. In conclusion, PSC dietotherapy could effectively alleviate the symptoms and lay a theoretical foundation for the development of an anti-constipation diet.