The intestinal mucosal barrier is the first barrier between the intestine and the external environment, preventing harmful substances and pathogens from entering the internal environment and maintaining intestinal homeostasis. Bile acids, synthesized from cholesterol in the liver and subsequently converted into secondary bile acids by gut microbiota, interact with bile acid receptors and the gut microbiome, playing a key role in maintaining the homeostasis of the intestinal mucosal barrier. This review will elaborate on the role of bile acids and bile acid metabolism in the structure of the intestinal mucosal barrier, as well as the relationship between bile acids and intestinal diseases, aiming to provide insights for future strategies in the prevention and treatment of intestinal barrier dysfunction and associated intestinal diseases.