Early stage colon cancer usually has no obvious symptoms, only slight discomfort, indigestion and occult blood in stool, etc. The clinical manifestations in the middle and late stage are usually change of defecation habit, blood in stool, gastrointestinal lesions, abdominal mass, etc. 1.Change of defecation habit: The growth of tumor cells in the colon of colorectal cancer patients will hinder the discharge of stool, and generally patients will treat the early symptoms of colon cancer, especially left hemicolectomy and rectal cancer, as ordinary constipation, which delays the treatment. 2.Blood in stool: persistent and chronic stool with mucus and blood, occasionally just discharge some mucus or blood. Especially for rectal cancer, about 80% of them are accompanied by blood in stool or mucus and blood in stool. 3.Gastrointestinal symptoms: abdominal distension, hidden pain and indigestion. Especially for right hemicolectomy cancer, the initial intermittent pain slowly turns into continuous pain, just like the chronic appendicitis pain in the right lower abdomen. In the case of left hemicolectomy cancer, the abdominal pain is generally colic, abdominal distension, hyperactive bowel movement, constipation, blood in stool, etc. 4.Abdominal mass: Colon cancer patients have hard masses and irregular shape, and more than half of colon cancer patients will have abdominal masses. The symptoms of colon cancer have a lot to do with the location, age and pathological type of the lesion.