Abstract: The surgical treatment principle of colorectal cancer has always been to remove the intestine with tumor locating and the adjacent mesentery. However, the optimal area of mesen-tery resection and the optimal range of lymph node dissection are still controversial. At present, there are two main theories of lymph node metastasis of colorectal cancer, including the Halsted metastasis model and the Fisher metastasis model. The Halsted metastasis model indicates that the tumor always metastasizing from the primary focus to the paraintestinal lymph nodes, then to the intermediate lymph nodes, central lymph nodes, and finally distant metastasis. The Fisher metas-tasis model, on the other hands, suggests that tumor metastasis may occurring in the early stage of tumor and may be random events. If Fisher′s model is established, lymph node dissection in traditional colorectal cancer surgery is only a step to determine the tumor stage, which is unlikely to affect the prognosis of cancer patients. The latest research data shows that lymph node metastasis and liver metastasis of colorectal cancer originating from different cell subsets of primary tumor, and the circulating tumor cells and its DNA can be detected in early stage of colorectal cancer. Therefore, the diagnosis and treatment of colorectal cancer has moved towards to the biology‑based surgery. The biology‑based surgery refers to the implementation of surgical treatment according to the results of tumor gene analysis or molecular immunoassay while making accurate diagnosis, so as to improve the prognosis and quality of life of patients by changing the timing, indications and methods of surgery. More and more biological and clinical research evidences are applied to guide the surgical timing and operation mode of colorectal cancer. Based on clinical practice and literature analysis, the authors believe that the biology‑based surgery of colorectal cancer is still in its infancy, and with the development of gene sequencing technology and the revelation of the pathogenesis of colorectal cancer, the biology‑based surgery will play a more important role in colorectal cancer.