The staging of gastric cancer is based on the analysis of the patient’s survival. There are many studies exploring the influence of malignant tumors and various factors of patients on survival status, and after continuous summing up, it is found that the depth of tumor invasion, lymph node metastasis and distant metastasis are the most important factors affecting patients’ survival. Through international academic conferences, a staging system including the above three factors (TNM staging system) was determined. It is worth noting that this staging is based on surgical resection of the specimen. T is the depth of tumor invasion. Gastric cancer grows from the epithelial cells on the inside of the stomach lumen and gradually invades outward. The stomach wall is divided into several layers from the inside to the outside, and T staging is determined according to the depth of tumor invasion. The deeper the depth of invasion, the more advanced the tumor is, and the greater the possibility of lymph node metastasis or other metastasis. N refers to the lymph node metastasis of the tumor. n staging was once defined in different ways, initially according to the number of lymph node metastases within different distances around the tumor, and later using the number of lymph node metastases for staging with reference to the location where the lymph nodes are located. The higher the number of lymph node metastases, the more advanced the disease. M refers to the distant metastasis of the tumor. If the tumor metastasizes to distant organs other than stomach, including liver, lung, bone, brain, adrenal gland, peritoneum, etc., it is distant metastasis. This condition means it belongs to the traditional advanced stage of tumor and the treatment effect is very poor. In academic circles, Japanese gastric cancer staging is also commonly used. Initially, Japanese gastric cancer staging was divided into different stations according to the location of lymph nodes, which is a good guidance value for radical surgery of gastric cancer, especially the scope of lymph node dissection. After years of communication and exchange between Eastern and Western gastric cancer scholars, the Japanese and UICC staging gradually merged, and the Japanese gastric cancer staging also accepted the N-staging method based on the number of lymph node metastases. The unified staging system provides an authoritative standard for the worldwide horizontal evaluation of gastric cancer efficacy and is invaluable in promoting clinical research of gastric cancer.