Gastric cancer is a common tumor of the digestive system, especially one that is highly prevalent in Asia. With the improvement of clinical research level in Asia as well as in China, and the increase of communication between the East and the West, the international attention to the treatment of gastric cancer has increased significantly. The treatment principle of gastric cancer is mainly based on the stage of gastric cancer, while paying attention to the principle of individualization of treatment. The biggest problem of gastric cancer treatment in China is that the early diagnosis rate is very low, which differs greatly from that of Japan, and the main means of early diagnosis and screening of gastric cancer is gastroscopy, which has low capital investment but low acceptance by patients. Principles of gastric cancer treatment: Stage 0 and I gastric cancer is mainly treated by radical surgery, and regular review after surgery is not required for post-surgical adjuvant treatment. For early gastric cancer combined with H. pylori (Hp) infection, it is also recommended in China that patients with local resection or major gastric resection should undergo postoperative treatment to remove H. pylori infection. In stage II-III gastric cancer, after radical surgery, postoperative adjuvant chemotherapy + radiotherapy, preoperative and intraoperative chemotherapy or radiotherapy can also be done. Stage IV gastric cancer is mainly treated with chemotherapy, palliative surgery or radiotherapy if necessary, together with the best supportive treatment. Guidelines of postoperative adjuvant chemotherapy for gastric cancer: (1) For patients with T1 and N0, no chemotherapy is done after surgery, medical observation and regular review. For early gastric cancer combined with Helicobacter pylori (Hp) infection, postoperative treatment to clear Hp infection should also be recommended in China for patients with local resection or major gastric resection. (2) Patients with T2 and N0 who do not have high-risk factors after surgery can be followed up and observed. If high-risk factors are present, postoperative adjuvant chemotherapy or radiotherapy is recommended. The high-risk factors are: low tumor differentiation or high histological grade, lymphovascular infiltration, nerve infiltration, and age less than 50 years. (3) Patients who achieve R0 resection for T3, T4 or any with lymph node metastasis should receive postoperative chemotherapy or radiotherapy. (4) Patients with R1 resection and R2 resection without metastasis should receive postoperative radiotherapy + chemotherapy. (R1 resection refers to tumor residue under microscope, R2 resection refers to tumor residue with naked eye). (5) The chemotherapy regimen for gastric cancer is based on fluorouracil-based drugs.