Colorectal cancer is a common type of cancer in clinical practice and has many causes, such as genetic factors, poor living habits, improper diet, and accumulation of chronic diseases over a long period of time. There is no clinical food that can prevent colorectal cancer, but patients can correct the dietary causes that may cause colorectal cancer through reasonable diet to reduce the chance of developing colorectal cancer. Therefore, patients can improve their dietary structure and add more food fiber and lactobacillus to reduce the chance of colorectal cancer caused by improper diet. Most vegetables and coarse grains contain a certain amount of dietary fiber, which can be consumed in appropriate amount to promote digestion and reduce the chance of colorectal cancer caused by improper diet. Especially, foods rich in water-soluble food fiber pectin, such as apples, oranges, oranges, grapefruit, okra, carrots, cauliflower, etc., have a certain role in promoting the regulation of intestinal flora; 2. Lactobacilli: such as cheese, yogurt and other dairy products or soy milk, tempeh and other soy products, which are rich in lactobacilli have a certain auxiliary role in regulating the structure of intestinal flora and improving intestinal function, which can reduce to a certain extent the risk of colorectal cancer caused by flora accumulation. 3, antioxidant substances: such as carrots, nuts, fish oil and other antioxidant substances rich in carotene, vitamin B2, vitamin C, vitamin E, etc., have a certain protective effect on the colonic mucosa, thus assisting in improving the stimulation of the colonic mucosa by diet; 4, high-calcium food: such as milk or other dairy products, etc., some studies have found that the daily increase in the amount of calcium supplement It has been found that the incidence of colorectal cancer is lower in people with moderate daily increase of calcium supplement and it has a certain auxiliary effect on prolonging the life of rectal cancer patients. It is recommended that patients should avoid smoking and drinking alcohol, increase exercise in moderation, avoid a diet that is too greasy or stimulating, and go outdoors to receive sunlight appropriately, which can also play a role in reducing the chance of developing colorectal cancer. If the patient has long time constipation, it may increase the chance of colorectal cancer, so it is recommended to seek medical treatment in time.