There are no natural or synthetic nutritional products hiving efficacy for treating cancer, but there is substantial evidence to support that a healthy diet and regular exercise can effectively prevent and delay tumor growth, improving the quality of life of patients. Cancer and treatment for cancer patients will cause cancer-related malnutrition. We need to take advantage of dietary intervention, according to the impact of cancer and chemotherapy patients function, combined with China's dietary guidelines and the latest research progress of anti-cancer diet, develop a reasonable diet, and nutritional supplements such as glutamate stressed, omega-3 unsaturated fatty acids, prebiotics, calcium and selenium can improve patient health. Cancer and treatment of cancer will cause severely effect on the patient's body, and the body's biochemical and physiological reactions will have adverse changes in the quality of life of patients with cancer development or treatment undertaken deteriorating. Cancer-related malnutrition can cause deterioration of the cancer, and the deterioration of the complex interactions involved in pro-inflammatory cytokines and the host metabolism. Nutrition experts from the American Cancer Center believe that approximately 40% of cancer patients die from malnutrition, but not the cancer itself. Studies have shown that: applied Nutrition support of patients during chemotherapy reversal of negative nitrogen balance, reduce toxicity, improve the patient's sensitivity to chemotherapy and survival. Malnutrition often leads to postoperative mortality and morbidity, chemo radiation incidence of adverse reactions, increased incidence of depression, prolonged hospitalization and readmission short-term increase, seriously affecting the quality of life of patients, even reducing the survival.