Whether chemotherapy should be administered after colon cancer surgery depends mainly on the stage of the tumor and the thoroughness of the surgery. The stage of tumor mainly includes the depth of tumor invasion, whether it is confined within the intestinal wall or has penetrated the plasma membrane of the intestinal wall, the former is still relatively early, the latter has a higher chance of recurrence and metastasis and needs additional adjuvant chemotherapy; secondly, whether there is metastasis in the lymph nodes within the resected intestinal mesentery and the number of metastasis, according to the regulations, pathologists need to examine more than 12 lymph nodes, if none of them has metastasis, then it is relatively early. If there are no metastases, it is relatively early. If there are 1-3 lymph nodes or even more than 3 lymph nodes metastases, especially if there are distant lymph nodes metastases away from the tumor, it is more problematic, and it is better to add adjuvant chemotherapy to reduce the risk of recurrence or metastases after surgery. In addition, it is also necessary to see whether there is nerve and vascular invasion in the tract and whether there is cancer embolism in the vasculature. If there is, it indicates that the chance of recurrence and metastasis will be significantly increased and additional chemotherapy is recommended. Finally, whether there are distant metastases such as liver, lung and abdominal cavity. If there are already clear or suspected metastases, chemotherapy is recommended as early as possible to control the growth of tumor. Also the thoroughness of surgical resection is very important, even if the tumor is not too early locally but very thoroughly resected, adjuvant chemotherapy will not help much to further improve the survival rate. However, if for various reasons the tumor cannot be removed cleanly and completely, and there may be tumor residue, then additional chemotherapy is necessary. Of course, for adjuvant chemotherapy, it is aimed to further improve the effect of surgery, increase the survival rate, lower the recurrence rate and distant metastasis rate, and is only applicable to patients with mid to late stage bowel cancer. And whether to do it or not also depends on the patient’s age and general condition. If there are many chronic diseases and the general condition is relatively poor, it is necessary to weigh its risks and benefits in a comprehensive manner and decide whether to do it or not.