Abstract: As the common side effect of radiotherapy for abdominal and pelvic tumors, radiation-induced intestinal injury (RIII) has seriously affected the subsequent therapy for cancer patients and the life quality of survivors. The number of patients with RIII are far exceeded those with inflammatory bowel disease, and there is an urgent need for effective treatment. Evidence supporting a pivotal role of the gut microbiota in the development of RIII has been growing. Fecal microbiota transplantation (FMT) has been confirmed to restore the abundance and diversity of patients' microbiota, and has become a potential method in the treatment of RIII. In this review, we put foward our current understanding of the role and mechanism of intestinal microbes in RIII and the application of FMT in the treatment of RIII.