At present, from the statistics of malignant tumors in Shanghai in 2010, cancer ranks high as the second cause of death of Shanghai residents, among which colorectal cancer has the second highest incidence rate and the third highest mortality rate. From the analysis of the trend of global disease spectrum changes, with the improvement of economic level and the change of diet structure, the incidence of colorectal cancer in China has also increased significantly, similar to the disease change trend in Europe and America and other developed countries. Despite the current update and improvement of multidisciplinary diagnosis and treatment concepts such as diagnosis of colorectal cancer, radical surgery in line with evidence-based medicine, postoperative adjuvant radiotherapy and gene therapy, the overall 5-year survival rate of colorectal malignancies still hovers around 50%. From the analysis of factors directly related to death of colorectal cancer itself, the main factors are distant organ metastasis, postoperative local recurrence and lymph node metastasis. We know that radical surgery is one of the main methods and means of systemic treatment for colorectal cancer. In the past, patients with advanced colorectal cancer combined with liver, lung and other organ metastases can only be treated palliatively or symptomatically, but now some of them still have the opportunity to obtain long-term survival through conversion therapy followed by simultaneous or heterochronic surgical resection. Depending on the preoperative stage, lesion size and location, and patient’s physical condition, the surgical treatment of colorectal cancer can be endoscopic resection, transanal local resection, laparoscopic or open surgery for radical treatment, depending on whether the cancer is early or progressive. The gastrointestinal surgeon will give a detailed postoperative adjuvant treatment and follow-up plan based on the postoperative pathological staging and the patient’s specific conditions. There is a certain rate of recurrence and metastasis after colorectal cancer surgery, and the local recurrence time is often within 1 to 2 years. Postoperative recurrence and metastasis are mainly related to factors such as biological characteristics of the primary cancer, staging at the time of surgery, location of the lesion, whether it is accompanied by occult metastasis and whether the surgery is complete or not. Recurrent metastases are mostly in the form of peri-anastomotic, original surgical area, perivascular or retroperitoneal lymph node metastases and hematologic metastases to distant organs. Combining with the current advanced diagnostic instruments, surgical concepts and equipment, and multidisciplinary means such as postoperative radiotherapy treatment with reference to international consensus, it is especially important to provide planned, sequential, thorough and individualized adjuvant treatment and follow-up after colorectal cancer surgery, so as to be able to diagnose early recurrent metastases and provide early and diversified treatment to achieve a satisfactory prognosis. Many patients or family members will consult whether radiotherapy should be performed after surgery. At present, the international as well as domestic expert consensus agrees that adjuvant radiotherapy intervention is needed for postoperative pathological staging of colorectal cancer as stage II high-risk, stage III and stage IV, and the so-called stage II high-risk is those with acute and chronic colonic obstruction after surgery, poor pathological type of tumor, presence of cancer thrombus in the resected colorectal specimen vessels or lymphatic vessels and the presence of high-risk factors such as the completeness of surgical resection or insufficient number of lymph nodes removal, must also be treated with postoperative adjuvant chemotherapy. For patients with rectal cancer, especially those with low level, tumor invading rectal mesentery and or with lymph node metastasis, and those who have not undergone radiotherapy before surgery, these patients also need adjuvant radiotherapy intervention after surgery. Follow-up is a very important part of the postoperative treatment of colorectal cancer, which can detect possible recurrent metastases at an early stage so that targeted treatment can be taken at an early stage. Regardless of early or progressive colorectal cancer patients, expert consensus recommends that tumor-related markers such as CEA and CA199 be tested every 3-6 months for two years after surgery, chest X-ray and enhanced examination of the surgical site of the primary cancer and CT of the liver be performed every six months, and annual fiberoptic colonoscopy is required. For patients with postoperative adjuvant radiotherapy, blood routine, liver and kidney function and other relevant blood index tests should also be tested during each cycle of chemotherapy. The gastroenterologist will also make individualized decisions on further laboratory or imaging tests, such as PET-CT, to rule out possible local recurrence or distant metastases at each follow-up visit based on the patient’s symptoms, the specialist’s physical examination and the corresponding physical and chemical tests. Patients should also pay attention to any abdominal pain and discomfort, loss of appetite, poor appetite and fatigue, blood or mucous jelly in the stool or masses in the abdominal wall in their daily life after surgery, and should be followed up promptly.