The incidence of malnutrition in patients with radiotherapy for tumors is high and the core concept of radiation nutrition for tumors is to prevent diagnose treat evaluate and detect malnutrition in patients with radiation for tumors so as to reduce the toxic side effects of radiotherapy and increase the efficacy of radiotherapy. Radiotherapy is a 􀆵 double - edged sword for nutrition with positive and negative effects. Improving malnutrition is of great significance for tumor radiation therapy which can significantly improve the efficacy of tumor treatment and improve overall survival. Radiation nutrition requires the establishment of an multidisciplinary team and standardized diagnosis of radiation nutrition should be combined with patient -generated subjective global assessment score and Radiation Therapy Oncology Group criteria. The selection of enteral nutrition access follows the 􀆵four-step model and the influence of the irradiation field should be considered when selecting the parenteral nutrition pathway. Nutritional regimens for patients undergoing radiotherapy for tumors should be considered in a combination of 􀆵energy glycolipid-to-energy ratio protein vitamins and immunonutrients . Patients with radiotherapy for tumors need to manage the whole process of nutrition during the 􀆵 peri - radiotherapy period and do a good job in the detection and follow-up of radiation nutrition. The author believes that the development of tumor radiation nutrition should focus on basic research clinical criterion and translation research in order to help improve and standardize the level of clinical radiation nutrition and benefit the majority of tumor patients.