Gastric cancer is the fifth most common cancer in the world, and chemotherapy is one of its main treatments. However, due to the side effects of chemotherapy drugs, about 87% of patients have malnutrition. Although the concept of nutrition therapy continues to advance, it still lacks sufficient attention, resulting in a low cure rate of malnutrition in gastric cancer patients. As an independent risk factor of death for gastric cancer patients, malnutrition not only leads to poor clinical outcomes, but also causes a huge social and economic burden. This review summarized the nutritional support treatment of gastric cancer patients undergoing chemotherapy in recent years, including the selection of nutrition evaluation tools, methods and effects of nutritional treatment, and made a prospect for its widespread clinical application in the future.