The incidence rate of cancer in China is increasing, and there is still a lack of effective treatment means, so the prevention of some high incidence cancers has become a top priority. There is a part of the population that we should pay more attention to, that is, the family members of cancer patients. Firstly, according to the current progress of medical research, cancer has a familial character, for example, breast cancer patients’ maternal relatives have a higher chance of suffering from breast cancer; and the incidence rate of stomach cancer in the close relatives of stomach cancer patients is 4 times higher than that of the general population. Although cancer has certain family factors, cancer is generally not directly hereditary. The role of genetic factors in the development of most tumors is the susceptibility or predisposition to cancer-causing factors, i.e., among people with the same living conditions, some individuals have a tendency to be more susceptible to cancer. On the basis of certain hereditary characteristics, whether cancer is formed or not also depends on the combined effects of many acquired factors and external carcinogens, such as mental factors, environmental factors, dietary factors and living habits. Second, the same living environment Cancer patients and their families live in the same environment, such as urban residents breathing air is seriously polluted will lead to a high incidence of lung cancer. Formaldehyde, benzene and other chemicals produced by the renovation of the toxicity of the living environment inside and outside a variety of radiation, noise, family members of smokers on the impact of passive smokers, far from the natural deep living in downtown areas, scarce greenery, the air in the serious lack of negative oxygen ions, etc. will play a certain impact on the occurrence of tumors. Third, similar lifestyle, such as dietary habits, meat more, vegetarian fiber less, such dietary habits are prone to digestive system tumors such as colorectal cancer, gastric cancer, rectal cancer, pancreatic cancer; eating fast, often eat hot food, pickled and smoked foods are prone to esophageal cancer, gastric cancer. Fourth, the character traits of similar ways of thinking The continuous stimulation of long-term bad mood or a short period of intense mental blow will produce a stress reaction, damage the immune function, resulting in cancer caused by gene mutation. How to avoid this situation is related to each person’s psychological quality and mentality, and its related character traits, way of thinking also has a certain genetic correlation as well as subtle influence. Fifth, the same precancerous lesions such as viral hepatitis can easily cause liver cancer, human papilloma virus is a high incidence of cervical cancer, gastritis caused by Helicobacter pylori can lead to gastric cancer, etc. And the viruses and bacteria that lead to these precancerous lesions are contagious to a certain extent, so family members of cancer patients are more likely to be infected with them. Sixth, the concepts of health care and preventive knowledge are similar, and there is a lack of attention to the concept of cancer prevention. Due to different cultural level, professional knowledge, economic status and social status, family members may have more or less knowledge about general medical knowledge and cancer prevention. Some people think that cancer is not preventable or do not realize that cancer is a systemic chronic disease from quantitative change to qualitative change due to the accumulation of many kinds of cancer-causing toxins from the outside, the worsening of endocrine disorders and the decreasing of immune function within the human body, and the transformation of healthy cells to sub-healthy cells, to pre-cancerous cells, and then to cancerous cells until the formation of tumors, infiltration, metastasis, and diffusion of tumors. The quantitative stage of tumor formation is the critical period for people to play a leading role in preventing cancer formation, and it is also the time when twice the effort is half the result. People with a family history of cancer do not necessarily get cancer, and susceptible people and family members of cancer patients are not susceptible to any cancer. For people with a family history of cancer, there is absolutely no need to panic and carry a heavy burden of thought. However, from the perspective of prevention, early detection of these high prevalence factors and timely preventive measures will certainly help reduce the incidence of cancer. According to the World Health Organization, 1/3 of cancers can be prevented, 1/3 can be cured, and 1/3 can be treated to improve symptoms, prolong life, and improve the quality of life. Therefore, in our daily life, we should keep away from cancer-causing factors, maintain a good mental state, have a reasonable diet, pay attention to the targeted selection of food with anti-cancer effects, choose appropriate exercise methods, mobilize the positive anti-cancer factors in our body, and continuously improve our body’s immunity, so that we can avoid the occurrence of cancer to the greatest extent possible.