The main reasons for the occurrence of colorectal cancer include malignant transformation of benign adenoma into cancer; excessive fat and refined carbohydrates in the diet, lack of refined fiber, which is not conducive to defecation and carcinogenic substances remain in the intestinal canal for a long time, stimulating the intestinal mucosa and leading to cancer; rectal polyps, ulcerative colitis and other induced colorectal cancer; familial genetic factors. In the early stage of colorectal cancer, the lesions are limited to the mucous membrane, and there may be no symptoms or only changes in bowel habits. However, in the middle and late stage, there will be the following symptoms: 1.Pus and blood stool and mucus stool due to mucosal erosion of intestine or even tumor rupture; difficulty in defecation, constipation and diarrhea or alternating symptoms of both. 2.As the size of colorectal cancer increases, the shape of bowel movement becomes thin and deformed. 3.Due to local invasion of cancer, irritation of intestine and intestinal obstruction, abdominal pain, dull pain and colic may appear. 4.A lump appears in the abdomen, when the cancer body is not adherent to other organs or tissues, it can still be pushed, but on the contrary, it is more fixed. 5.As the disease worsens, patients will show chronic wasting signs such as anemia, emaciation, weakness and fever. 6.When colorectal cancer develops to the middle and late stage, it may also lead to complications such as mechanical intestinal obstruction, acute colon perforation, peritonitis and acute hemorrhage due to the increase of volume or malignant transformation. Periodic physical examination and colonoscopy screening are very important for early detection, early diagnosis and early treatment of intestinal tumors, which can greatly improve the survival rate! Minimally invasive radical surgery is feasible for early detection, while open surgery for late detection is very traumatic in terms of tumor radical treatment, some people mistakenly believe that minimally invasive cannot completely solve the problem of radical treatment. In fact, due to the magnifying effect of laparoscopy, with good exposure, laparoscopy can often achieve finer and more thorough surgery than traditional open surgery. It can clearly see the tiny lymph nodes and accurately remove them; a large amount of clinical data proves that the scope of laparoscopic surgery for colorectal cancer and the number of lymph nodes cleared are no different from those of open surgery; the incision is smaller and the postoperative pain of patients is greatly reduced, so the recovery after surgery is greatly accelerated and the surgery is superior to traditional open surgery. However, the technical requirements of laparoscopy are high, and the operator must have both rich experience in open surgery, anatomical basis, and skillful laparoscopic operation skills. In the case of skilled technical operation, laparoscopic surgery is preferred for most cases of general abdominal surgery.