Abstract: The digestive system provides energy for systemic metabolism and maintains life needs through digestion, absorption, material conversion and other functions. There is a physical barrier between the mucosal epithelium or endothelium of the digestive system. This physical barrier can prevent harmful substances from invading the digestive tract mucosa and reduce the occurrence of digestive system diseases. Its structure mainly includes tight junction, gap junction, adhesive junction and desmosomes. Tight junction plays a major role in maintaining the functional stability of mucosa. The translocation of pathogenic microorganisms, the invasion of endotoxin and macromolecular substances and drugs eventually lead to digestive system diseases by destroying the tight junction structure and function between two adjacent cells. Tight junction is a structural complex, including membrane proteins and cytoplasmic proteins. In recent years, there have been many studies on the relationship between tight junction related proteins and digestive system diseases. This paper mainly expounds the relationship between zonula occludens-1 (ZO-1) in tight junction and digestive system diseases.