Many diseases can kill a person, especially cancer, for which there is no clear treatment today with advanced medical science. Stomach cancer is one of the most common malignant tumors in China, and its incidence rate ranks the 3rd among all kinds of tumors in China, accounting for the first place of gastrointestinal malignant tumors. About 170,000 people die of stomach cancer in China every year, which is close to 1/4 of all malignant tumor deaths, and more than 20,000 new stomach cancer patients are produced every year. Gastric cancer can occur at any age, but it is more common in 40-60 years old, more men than women, about 2:1. Gastric cancer can occur in any part of the stomach, most commonly in the sinus (48.8%-52.5%), followed by the cardia (16.1%-20.6%), and the average life expectancy of untreated patients is about 13 months. The etiology of gastric cancer has not been fully elucidated so far, and a lot of research data show that the occurrence of gastric cancer is the result of a combination of factors, including: 1) External factors: (1) Dietary factors: The possible dietary carcinogenic factors are frequent consumption of smoked and baked foods (containing benzo(a)pyrene) or pickled foods and sauerkraut (containing N-nitroso compounds). Salted foods high in salt are considered to be another risk factor for the development of gastric cancer. Recent studies have proposed additional protective factors, such as milk, animal protein, fresh vegetables and some fruits. (2) Helicobacter pylori infection: In recent years, it is generally believed that H. pylori infection is related to the development of gastric cancer. 1994 WHO has listed it as the first category of gastric cancer risk factors. Domestic and foreign epidemiological survey data show that the incidence of gastric cancer is positively correlated with the rate of HP infection, and the risk of gastric cancer is 6 times higher in HP-infected patients than in non-infected ones. (3) Other factors: fungus, schistosomiasis, geographic environment factors, as well as social, economic, psychological and dietary behaviors and habits play a role in the development of gastric cancer. (2) Intrinsic factors: (1) Genetic factors and genetic variants: there is a tendency of family gathering in the development of gastric cancer, and the incidence rate of gastric cancer among patients’ family members is 2 to 4 times higher than that of the general population. (2) Dysregulation of apoptosis and proliferation; (3) Immune dysfunction and hypoplasia; (4) Role of digestive tract hormones; (5) Disease factors: It is now recognized that patients with some diseases have an increased incidence of gastric cancer, so they are regarded as precancerous lesions, also known as precancerous state. Such patients are considered as high-risk group. They include chronic atrophic gastritis, gastric ulcer, gastric polyp, remnant stomach and hypertrophic gastritis, etc. 3.Intestinal epithelial metaplasia and heterotypic hyperplasia: The development of gastric cancer from normal gastric mucosa is a long and gradual process, and certain transitional lesions appearing in this process are called precancerous lesions. It is now believed that intestinal epithelial hyperplasia and heterotypic hyperplasia of gastric mucosa have precancerous significance, while the latter is more significant. The grading of heterogeneous hyperplasia is not uniform and is subjective. Domestically, there are 3 grades of mild to moderate severity. The endoscopic follow-up results show that the cancer rate is 2.5% for mild, 4%-8% for moderate, and 10%-83% for severe. Gastric cancer starts from the epithelial layer of mucosa, and the cancer foci gradually develop and infiltrate and spread horizontally and deeply at the same time, gradually involving all layers of the stomach wall and even the surrounding organs, and can also metastasize through various ways. The early stage of the disease has a great influence on the efficacy and prognosis. According to the depth of invasion of gastric cancer into the stomach wall, it is divided into early stage gastric cancer and progressive stage gastric cancer. Those invading to a depth not exceeding the submucosa are called early gastric cancer, those invading to the muscular layer are called intermediate gastric cancer, those invading to the plasma membrane and beyond the plasma membrane are called advanced gastric cancer, and intermediate and advanced gastric cancer together are called progressive gastric cancer. Early gastric cancer is mostly asymptomatic or with only mild symptoms. About 80% of patients in early stage show upper abdominal discomfort, and nearly 50% of patients with gastric cancer have obvious, loss of appetite or loss of appetite. In late stage, weakness, low back pain and nausea, vomiting and difficulty in eating may appear after obstruction. Vomiting blood and black stool appear when the tumor surface is ulcerated. When clinical symptoms are obvious, the lesion is already in advanced stage. Therefore, we should be very alert to the early symptoms of gastric cancer to avoid delaying the diagnosis and treatment. Fiberoptic endoscopy is the most direct, accurate and effective diagnostic method to diagnose gastric cancer. Abdominal CT examination, trans-laparoscopic examination helps to understand the invasion of gastric tumor, the relationship with surrounding organs and the possibility of resection. The principle of comprehensive treatment should be adopted, that is, according to the pathological type and clinical stage of tumor, combined with the general condition and functional status of patient’s organs, multidisciplinary comprehensive treatment (MDT) mode should be adopted, and treatment means such as surgery, chemotherapy, radiotherapy and biological targeting should be applied in a planned and reasonable way to achieve the purpose of radical or maximum control of tumor, prolong patient’s survival and improve the quality of life. Surgical resection is the main treatment for gastric cancer and the only way to cure gastric cancer at present, and there are two ways: traditional and laparoscopic. Gastric cancer surgery is divided into radical surgery and palliative surgery, and radical resection should be strived for. Radical surgery for gastric cancer includes EMR, ESD, D0 resection and D1 resection for early gastric cancer, (D2) and expanded surgery (D2+) for partially progressive gastric cancer. Palliative surgery for gastric cancer includes palliative resection for gastric cancer, gastrojejunostomy, jejunal nutrition tube placement, etc.