Radiotherapy is a key method in the treatment of malignant tumors which has significant benefits. It not only effectively reduces the burden of tumors and relieves related symptoms but also deeply affects the nutritional status of patients. However the process of radiotherapy complexly interferes with the intake digestion absorption and metabolism of nutrients which can easily lead to or aggravate malnutrition becoming a common complication of radiotherapy patients. In view of the significant negative impact of malnutrition on prognosis and quality of life it is essential to implement systematic and standardized nutritional assessment and intervention for radiotherapy patients. Therefore nutritional risk screening 2002 NRS 2002 scale is recommended as the preferred screening tool because of its scientific and practical nature. However the patient-generated subjective global assessment PG-SGA plays an important role in nutritional assessment due to its comprehensiveness and sensitivity and provides a basis for personalized nutritional intervention. In view of the dynamic changes in nutritional status of patients we advocate flexible strategies such as timely adjustment of treatment pathways optimization of enteral and parenteral nutrition support personalized energy and protein requirements setting reasonable supplementation of immune nutrients and encouraging patients to participate in physical activity. These comprehensive measures are aimed at comprehensively improving the nutritional status of patients during the perioperative period of radiotherapy reducing the adverse reactions of radiotherapy improving the tolerance of patients and enhancing the sensitivity of tumor cells to radiotherapy so as to optimize the therapeutic effect. Both in the short and long term they are expected to significantly improve the efficacy and ultimately improve the overall quality of life of patients.