Primary carcinoma of the liver is one of the common malignant tumors in China. It has a high mortality rate, ranking third after stomach and esophagus in the order of death from malignant tumors, and second after stomach cancer in rural areas in some regions. Every year, about 110,000 people die of liver cancer in China, accounting for 45% of all liver cancer deaths worldwide. Studies on the relationship between viral hepatitis and liver cancer have found that: 1. Hepatitis B markers in the serum of liver cancer patients are over 90% (only about 15% in the control group); 2. The chance of liver cancer in HBsAg-positive patients in areas with high incidence of liver cancer is 6 to 50 times higher than that of negative patients; 3. 4. X gene of HBV can change the gene expression of HBV-infected hepatocytes and may be related to carcinogenesis. The above shows that hepatitis B virus is closely related to liver cancer and is an important risk factor for the occurrence of liver cancer. Aflatoxin In areas with high incidence of liver cancer, especially in the southern corn-based grain local surveys suggest that the prevalence of liver cancer may be related to aflatoxin contamination of food, the urinary aflatoxin B1 metabolite aflatoxin M1 content of the population is very high; drinking water pollution Jiangsu Qidong ditch water drinkers liver cancer incidence rate of 60-101/100,000, drinking well water drinkers only 0-19/100,000. The relative risk of ditch water drinkers is 3.00. The investigation found that a kind of algae producing algae toxin in ditch water may be a clue of drinking water pollution and liver cancer occurrence. The disease develops rapidly and has a high mortality rate, which is a serious risk to life and health. Since it is difficult to explain the causes and distribution of liver cancer in China and around the world satisfactorily, the occurrence of liver cancer may be caused by multiple factors through multiple pathways; the cancer-causing and cancer-promoting factors may not be exactly the same in different regions, what are the main factors and how the factors are related to each other are yet to be studied.