Abstract: The treatment and related clinical research of gastric cancer in Japan have a long history and scientific continuity. Most clinical studies are organized and implemented by the Japan Clinical Oncology Group (JCOG) based on the principle of multidisciplinary argumentation, which helps to ensure the continuity of research, prevent misjudgment of research directions, and minimize the waste of research resources. The author reviews the development history of clinical study on gastric cancer in Japan and explores the promoting role of the Japanese Gastric Cancer Society and JCOG in clinical study on gastric cancer, aiming to provide reference and experience for peers.