Abstract: Intestinal flora is an important part of human body. It has been confirmed that intestinal flora plays important roles in the occurrence and development of hypertension, diabetes, tumor and inflammatory bowel disease. Radiation enteritis (RE) is more common in patients with tumor radiation and nuclear exposure. In recent years, the relationship between intestinal flora and RE has become a research hotspot. RE was closely related with intestinal flora. The mechanism may be closely related to the infiltration of inflammatory cells and the expression of related cytokines which were caused by the imbalance of intestinal flora. Probiotics supplement therapy can partially relieve the clinical symptoms of patients with RE. Some studies are exploring the therapeutic effects of fecal bacteria transplantation and small molecule new drugs in RE. This study summarizes the recent research on the pathogenesis and clinical application of RE based on intestinal flora, hoping to provide theoretical basis for the treatment of targeted intestinal flora.