In recent years， intestinal flora has gradually become the focus of research on the treatment of malignant neoplasms. Intestinal opportunistic pathogens （such asFusobacterium nucleatum，Bacteroides fragilis）， intestinal probiotics （such asClostridium butyricum，Lactic acid bacteria） and intestinal pathogenic bacteria （such asSalmonella，Shigella） can affect the efficacy and related adverse reactions of radiotherapy， chemotherapy and immunotherapy for the colorectal cancer （CRC） by influencing signaling pathways， modulating autophagy， regulating immune response， producing metabolites and toxins， and transplanting fecal bacteria. At the same time， it provides a large number of potential targets for targeted therapy of the CRC. Further research on the relationship between intestinal flora and non-surgical treatment of the CRC can provide references for basic and clinical research of non-surgical treatment of the CRC.