In recent years, common lung diseases are often accompanied by gastrointestinal dysfunction, which seriously affects the prognosis of patients. The relationship between lung diseases and intestinal mucosal barrier needs to be explored. This paper presents the composition of the intestinal mucosal barrier (including mechanical barriers, biological barriers, immune barriers, and chemical barriers), the effects and the mechanisms of lung diseases (pneumonia, asthma, chronic obstructive pulmonary disease, idiopathic pulmonary fibrosis) on intestinal mucosal function. The review aims to provide a theoretical basis for early detection and early treatment of gastrointestinal dysfunction.