Like other tumors, the occurrence of esophageal cancer is also related to internal and external factors. External factors are related to food, dietary habits and environment: (1) More frequent consumption of food containing strong carcinogenic substances such as nitrosamines, such as pickled food and sauerkraut. (2) More frequent consumption of aged food, mold and nitrosamines have a synergistic effect in promoting cancer. (3) Dietary habits that may lead to esophageal mucous membrane damage, such as long-term consumption of strong alcohol, hot food, coarse food, strong tea, pepper and other irritating foods, long-term untreated esophagitis can evolve into precancerous or malignant esophageal lesions. (4) The lack of some trace elements in the environment is found in the area with high incidence of esophageal cancer, and the lack of trace elements is also an important factor in the occurrence of cancer, and the lack of molybdenum in the soil and water in the area with high incidence of esophageal cancer. Endogenous factors are mainly related to genetic factors: esophageal cancer has a significant phenomenon of family gathering, and it is not uncommon for families with three or more consecutive generations of disease in high incidence areas.