In case of post-operative rectal cancer, it is generally necessary to fast water for 3-4 days, and the doctor generally recommends transitioning from liquid to semi-liquid diet within half a month after exhaustion, after which a normal diet rich in nutrients and light and easy to digest will be given according to specific conditions. I. Low salt and low fat to reduce the burden on the intestinal tract. Second, eat foods rich in dietary fiber, such as celery, leeks, baby bok choy and other green vegetables, which can promote intestinal peristalsis, reduce constipation and cleanse the intestinal tract. According to research, fats and oils can promote the growth of cancer cells, in addition to consuming more vegetable oils and less animal oils. Avoid grilled, smoked, fried and pickled foods, which can promote cancer to a certain extent. V. Quit smoking and alcohol. Eat more fresh vegetables and fruits, preferably seasonal ones, in line with the season, to supplement vitamins and other nutrients, which can help improve patients’ immunity and resistance, and help in the treatment of rectal cancer.