Self-diagnosis of bowel cancer is mainly through clinical manifestations, but this method has limited reference. It needs to be diagnosed by a combination of other methods. There are many types of bowel cancer, now take colon cancer which is common in gastrointestinal tract as an example. Early stage of colon cancer often has no specific symptoms, but in the late stage of development, there are the following symptoms: increased frequency of bowel movement, diarrhea, constipation, blood, mucus or pus in feces; inaccurate hidden pain; abdominal mass; symptoms of intestinal obstruction: abdominal distension, constipation, abdominal distension and paroxysmal colic. Systemic symptoms: anemia, lethargy, weakness, etc. In addition to clinical symptoms, the following diagnostic methods should be combined: colonoscopy, pathological biopsy of lesions found under the microscope, easier to diagnose. Ultrasound and CT are helpful to know whether there is metastasis or not. x-ray barium enema is of great significance to the diagnosis of colon cancer. Because there are generally no specific symptoms in the early stage of intestinal cancer, so in order to improve the accuracy of diagnosis, it is necessary to synthesize all kinds of diagnostic methods, so as to achieve early detection, early diagnosis and early treatment.