Liver cancer is a common malignant tumor with extremely high mortality rate, and it ranks the 3rd among the malignant tumors of digestive system. Every year, about 110,000 people die from liver cancer in China, accounting for 45% of the deaths from liver cancer worldwide. It can be seen that liver cancer has become a major killer threatening human health. Therefore, the question of how liver cancer is caused becomes very important. 1.Chronic liver disease: especially viral hepatitis is closely related to the development of liver cancer, which is called the “catalyst” of liver cancer by the medical profession, among which hepatitis B (HBV) and hepatitis C (HCV) are the most important. Therefore, hepatitis B virus and hepatitis C virus are regarded as one of the cancer-promoting factors, which are the causes of liver cancer. 2.Long-term consumption of pickled, fried and smoked foods can also induce liver cancer: nitrosamines contained in pickled foods and 3,4-benzopyrene contained in fried and smoked foods can induce cancer, so we should try to reduce the consumption of pickled, fried and smoked foods such as cured meat, grilled meat, baked sausage, salted fish and pickled vegetables in our daily life. 3.Cirrhosis: Medical observation shows that about 50%-90% of liver cancer patients have different degrees of cirrhosis, so cirrhosis is also regarded as a cancer-promoting factor, so patients with cirrhosis should do a good job of regular review to prevent the occurrence of liver cancer. 4. Consumption of spoiled food can also induce liver cancer: Studies have found that moldy food produces a toxic metabolite, aflatoxin, which is the strongest biological carcinogen found today, so moldy food such as peanuts, corn, rice, dried potatoes, dried turnips, dairy products and soybean products should be avoided. 5.Water pollution: Serious pollution of drinking water is one of the important causes of liver cancer, especially the contaminated ditch water, followed by river water and the lowest well water. Therefore, in villages without running water facilities, drinking well water should be promoted. Immune status: It is believed that the plasma of liver cancer patients contains a confinement factor, which can inhibit cellular immunity and protect liver cancer cells from being killed by immune cells. Now it has been proved that AFP can inhibit the phagocytosis of lymphocytes and macrophages. 7.Gene mutation: In recent years, it is also believed that the activation of hepatocyte division reaction pathway stimulated by mutagen and virus in the environment, which causes point mutation and gene translocation of cells, is a possible factor to accelerate the proliferation of cancer cells. 8.Other factors: excess nutrition (large amount of nutrients) or lack of nutrition (such as vitamin A and B1 deficiency), hemochromatosis, parasitic infection and genetics are also risk factors for liver cancer. In addition, excessive alcohol consumption leads to the accumulation of fat in the liver, which may cause fatty liver. At this point, continued development will lead to alcoholic hepatitis, which will intensify the damage to the liver. If not treated in time, it may develop into alcoholic cirrhosis, which may also turn into liver cancer at a later stage.