Gastric cancer is one of the common malignant tumors in China, and it ranks first among all kinds of malignant tumors in China. Every year, about 170,000 people die of gastric cancer, which is almost a quarter of all malignant tumor deaths, and more than 20,000 newborn gastric cancer patients are diagnosed every year. Gastric cancer can occur at any age, but it is more common in 40-60 years old, more in men than in women, about 2:1. Gastric cancer can occur in any part of the body, but it is more common in gastric sinus, especially in the side of gastric recess, and it is divided into early gastric cancer and progressive gastric cancer according to the infiltration depth of cancer tissue. Early symptoms of gastric cancer are often not obvious, such as elusive upper abdominal discomfort, hidden pain, belching, acidity, loss of appetite, mild anemia, etc. Some of them are similar to symptoms of gastroduodenal ulcer or chronic gastritis, and some patients take painkillers, anti-ulcer drugs or diet adjustment to reduce or relieve pain, so they are often ignored without further examination. As the disease progresses, the symptoms of stomach become obvious, such as upper abdominal pain, loss of appetite, emaciation, weight loss and anemia. At the later stage, there is often metastasis of cancer, abdominal mass, enlarged left supraclavicular lymph node, black stool, ascites and severe malnutrition, etc. Since gastric cancer is very common and harmful in China, and the relevant research believes that its causes are related to dietary habits and stomach diseases, it is very important to understand the basic knowledge about gastric cancer for its prevention and treatment. The diagnosis of gastric cancer relies on gastroscopy, and because of the early symptoms of gastric cancer are not obvious, and because of the economic situation and health awareness in China, the proportion of early gastric cancer in China is low, less than 10%, and the current situation of gastric cancer diagnosis and treatment in China is characterized by one high and three low. This is contrary to the principles of tumor prevention and treatment: early detection, early diagnosis and early treatment. Early detection lies in raising health awareness, timely examination of stomach symptoms to clarify the disease and exclude tumor, as well as routine health examination to exclude stomach cancer. The treatment of gastric cancer is a comprehensive treatment mainly based on surgery. If gastric cancer is detected early and treated by surgery in time, the five-year survival rate is almost close to 100%, and the scope of surgery is small, less traumatic and recovery is fast. The treatment of patients is individualized.