Colon cancer is a common malignant tumor of the gastrointestinal tract occurring at the junction of the rectum and sigmoid colon, with the highest incidence in the age group of 40 to 50 years old, and the ratio of men to women is 2 to 3:1. The incidence rate is the third highest among gastrointestinal tumors. Colon cancer is mainly adenocarcinoma, mucinous adenocarcinoma and undifferentiated cancer. The general morphology is polyp-like, ulcerated and so on. Colon cancer can develop along the circumference of intestinal wall, spread up and down along the longitudinal path of intestinal tube or infiltrate deeply into the intestinal wall. In addition to metastasis and local invasion via lymphatic vessels and blood stream, it can also spread and metastasize into the abdominal cavity or along the suture and incision surface. Patients with chronic colitis, colon polyps, and obese men are the susceptible groups. Postoperative adjuvant chemotherapy is required for patients with stage II colon cancer who have high-risk factors. Risk factors for stage II colon cancer include the following: (1) postoperative pathology indicates undifferentiated or hypodifferentiated tumor; (2) tumor with vascular infiltration (including blood vessels or lymphatic vessels); (3) preoperative intestinal obstruction; (4) pathological biopsy with less than 12 lymph nodes; (5) perineural infiltration; (6) local perforation of tumor; (7) tumor margin adjacent to tumor tissue or tumor (6) localized perforation of the tumor; (7) the cut edge is close to the tumor tissue or the tumor is not sure whether the cut edge is positive or the cut edge is positive.