1. viral hepatitis and cirrhosis Hepatitis B virus (HBV) and hepatitis C virus (HCV) are closely related to liver cancer and are important risk factors for the development of liver cancer. areas with high mortality rates of liver cancer are accompanied by high rates of HBV infection. HBV infection can directly lead to liver cancer without going through an intermediate sclerotic stage, although cirrhosis is present in most patients. In contrast, HCV-associated liver cancer always originates from severe fibrosis or cirrhosis. Cirrhosis caused by alcohol abuse and chronic active hepatitis increases the risk of HCC. 2. Aflatoxicity It is now widely believed that aflatoxin B can promote the development of HCC. In areas with a high incidence of liver cancer, especially in the south to corn-based grain local investigation suggests that the prevalence of liver cancer may be related to the mold of grain. Aflatoxin B1 is the most powerful carcinogenic agent of animal liver cancer. A large number of domestic epidemiological studies have found that high exposure to aflatoxin plays an important role in the occurrence of liver cancer and should be given due attention. 3, drinking water pollution Investigation found that the incidence of liver cancer is higher in those who drink ditch and pond water than those who drink deep well water. There is a kind of algae toxin produced by blue-green algae in ditch and pond water, which is a strong carcinogenic factor and is an important evidence of drinking water pollution and the occurrence of liver cancer. 4.Hereditary factors Sometimes there is a family gathering phenomenon of liver cancer in high incidence areas, especially the high rate of liver cancer among those who live together and are related by blood, suggesting that liver cancer has a genetic tendency and may also be related to vertical transmission of hepatitis virus. 5.Drinking alcohol and smoking Long-term drinking and smoking increase the risk of liver cancer, especially the risk of HBsAg positive patients.