Cancer is a major contemporary threat to human health, occurring mainly in middle-aged and elderly people. There are still many question marks about its etiology and pathology, and there is still a lack of effective treatment methods, and a cancer diagnosis is like a death notice in people’s eyes. Preventing cancer and improving the quality of survival have become the urgent tasks of the medical profession. Research shows that more than 80% of cancers are caused by environmental degradation and improper lifestyle. Therefore, it is possible to prevent cancer by avoiding bad habits, physical exercise, healthy diet, controlling alcohol consumption, avoiding excessive exposure to ultraviolet rays and quitting smoking, etc. 1. Reasonable dietary arrangement First of all, we should pay attention to dietary hygiene and keep the gate of “cancer enters through the mouth”. The diet should be diversified, not to be partial or picky, so that the nutritional composition of food is as complete and balanced as possible, neither lack of nutrition nor excess nutrition, more whole grains (coarse grains), mixed grains, beans, fresh vegetables and fruits, low-fat foods, fish, seafood, soy products, low-fat dairy products. Vegetables, fruits, cereals and legumes should account for more than 2/3 of the diet structure, and red meat (i.e. beef, lamb and pork) should not exceed 90 grams per day, and it is better to eat fish and poultry as an alternative to red meat. Do not eat overly hot, moldy, irritating food, and try to eat less fried, smoked, pickled, refined white rice and flour, high sugar, high fat food and food and drinks containing food additives. 2, maintain an optimistic mood have an open mind, overcome negative inferiority, pessimism and disappointment and other negative emotions, keep a smile on your face in life, should not be sad; cheerful and open-minded, should not complain about others. Some people love to take regret pills, blame others, or keep their unhappiness and depression inside themselves so that they can not be relieved and cathartic, which is tantamount to making cancer lurking in us as an ally. 3.Actively manage the environment and do a good job in personal protection Housing should be ventilated frequently, especially the kitchen should be better ventilated to avoid inhaling fumes as much as possible. The new house after renovation must be tested for indoor air. Try to avoid exposure to harmful and toxic chemicals, such as asbestos which can cause lung cancer, aniline dyes which can cause bladder tumors, benzene which can cause leukemia, etc. Avoid ionic rays and large amount of ultraviolet radiation, especially from the sun, which can cause skin cancer. 4. Quit smoking as early as possible Smoking is a well-known cancer-causing factor, and 30% of cancers are related to it. When the smoke of tobacco burning is inhaled, the tar particles will adhere to the bronchial mucosa, forming long-term chronic stimulation and inducing cancer. 5.Actively prevent and treat chronic diseases and reduce long-term chronic stimulation Treat precancerous lesions, such as heavy hyperplasia of esophageal epithelium, atrophic gastritis, chronic hepatitis and cirrhosis, colon polyps, hyperplasia and chemosis of bronchial epithelium, mucosal leukoplakia, chronic skin ulcers, fistulas, proliferative scars, rectal polyps, etc., to prevent their further development. 6.Strengthen the monitoring of susceptible people Middle-aged men are recommended to have annual checkups; if immediate family members (parents, siblings, children) suffer from cancer, they should have regular checkups as early as possible, preferably twice a year to monitor their bodies. If tumor signals and symptoms are found, early diagnosis and treatment should be carried out. 7. Moderate physical exercise should be adhered to Physical exercise helps to stimulate vitality, enhance physical fitness, improve immunity level and enable the organism’s organs to function in a comprehensive manner. Physical fitness itself is the best material basis to resist cancer. 8. Self-examination of tumor: The following symptoms should be taken as warning signs to draw attention to cancer tumor, and people should seek medical consultation promptly if they have the following discomfort or related symptoms: (1) Gradual increase of palpable lumps on body surface or superficially. (2) Persistent abnormal digestion or feeling of fullness in the upper abdomen after eating. (3) Sternal discomfort or even choking sensation when swallowing food. (4) Persistent cough with blood in the sputum. (5) Tinnitus, hearing loss, epistaxis, blood in nasopharyngeal secretions. (6) Occult blood in the stool, blood in the stool, hematuria. (7) Long-standing ulcers. (8) Short-term enlargement, deepening of color, hair loss, itching, and breakage of moles and warts. (9) Weight loss of unknown origin.