Principle: Surgical resection is still one of the main treatment means for comprehensive treatment of gastric cancer. Gastric cancer surgery is divided into radical surgery and palliative surgery. Radical surgery for gastric cancer includes EMR, ESD, D0 resection and D1 resection for early gastric cancer; standard radical surgery (D2) and extended radical surgery (D2+) for partially progressive gastric cancer. Palliative surgery for gastric cancer includes palliative resection of gastric cancer, gastrojejunostomy, jejunal nutrition tube placement, etc. Surgical procedures should be performed to completely remove the primary lesion and thoroughly clear the regional lymph nodes. For gastric cancer with limited growth, the margin should be at least 3 cm from the lesion; for gastric cancer with infiltrative growth, the margin should be more than 5 cm from the lesion; for gastric cancer adjacent to esophagus and duodenum, the lesion should be removed as completely as possible, and intraoperative frozen pathological examination should be performed if necessary to ensure that no cancer remains in the margin. Nowadays, D is still used to indicate the range of lymph node clearance, such as D1 surgery refers to clearing regional lymph nodes to station 1, D2 surgery refers to clearing regional lymph nodes to station 2, and if the requirement of lymph node clearance at station 1 is not met, it is considered as D0 surgery. Laparoscopy is a recently developed minimally invasive technique, and it is appropriate for patients with stage I gastric cancer. (1) Reduction surgery: all types of radical surgery with resection scope less than standard radical surgery; ① Endoscopic mucosal resection (EMR) and endoscopic submucosal resection (ESD) indications: highly differentiated or moderately differentiated, non-ulcerated, intra-mucosal cancer with diameter less than 2 cm and no lymph node metastasis; ② Gastric D1 resection indications: intra-mucosal cancer with diameter more than 2 cm, and invasion of mucosa (2) Indications for gastric D1 resection: intramucosal cancer with a diameter of more than 2 cm, and gastric cancer invading the submucosa. Once lymph node metastasis appears, D2 resection should be performed. (2) Standard surgery (D2 radical surgery) D2 radical surgery is the standard surgery for gastric cancer, and should be performed if the tumor infiltrates deeper than the submucosal layer (muscle layer or above), or if it is accompanied by lymph node metastasis but has not yet invaded the adjacent organs; (3) Standard surgery + combined organ resection: if the tumor infiltrates the adjacent organs; (4) Palliative surgery: only applicable to those with distant metastasis or tumor invading important organs that cannot be removed. (4) Palliative surgery: only for those who have distant metastasis or tumor invading important organs that cannot be removed and combined with bleeding, perforation and obstruction. The purpose of palliative surgery is to relieve the symptoms and improve the quality of life.