Colorectal cancer (CRC) is the fourth deadliest cancer in the world. Early detection of colorectal cancer can significantly reduce its mortality. Methylation of the SEPTIN9 gene is related to the occurrence and development mechanism of colorectal cancer. Therefore, detection of the SEPTIN9 gene methylation level in the peripheral blood can be used for the screening of colorectal cancer and for surgical efficacy evaluation and prognosis prediction. The studies on SEPTIN9 gene, mSEPT9 assay, clinical application and existing problems are reviewed in this paper. It is hoped that this article will provide clinicians with a preliminary understanding of SEPTIN9 and its related research on colorectal cancer,allowing them to select appropriate detection method and develop a method based on gene methylation as a breakthrough point.