Gastric cancer originates from the glandular epithelia of the stomach. In China, the incidence of gastric cancer ranks 2nd among all the malignancies, just below lung cancer. And it is still the 3rd leading cause of cancer-related deaths. There are approximately 1.2 million newly diagnosed cases of gastric cancer worldwide, 40% of which came from China. There are only 20% of gastric cancer diagnosed in its early stages, most of which are in advanced stage, and the overall 5-year survival rate is less than 50%. In recent years, with the popularity of gastroscopy, the proportion of early gastric cancer increased year by year. The overall strategy for treatment of gastric cancer is to provide comprehensive treatment based on surgery. This clinical guideline is formulated to further standardize the treatment of gastric cancer in China, improve the treatment level of gastric cancer and the prognosis of gastric cancer patients, and ensure the quality and safety of medical care. Gastric cancer in this guideline refers to gastric adenocarcinoma (hereinafter gastric cancer for short), including esophagogastric junction (EGJ) cancer.