Pancreatic cancer patients are at the highest risk of malnutrition among all cancer patients, and radiochemotherapy may further exacerbate the risk of malnutrition in these patients. Malnutrition can reduce the therapeutic efficacy of radiochemotherapy and increase adverse reactions, thereby adversely impacting patients’ quality of life and prognosis. Consequently, nutrition intervention is particularly crucial in the management of pancreatic cancer. Researches have shown that nutrition intervention can effectively ameliorate cachexia associated with pancreatic cancer, reduce the risk of malnutrition, and thereby maintain the sensitivity and tolerance to radiochemotherapy, alleviate adverse reactions, and reduce the complications of adjuvant therapy and surgical treatment. The combination of nutrition intervention and radiochemotherapy can disrupt the metabolism of pancreatic cancer and inhibit tumor growth, reduce the hospitalization rate of patients, and improve their quality of life. This review discusses the methods of nutritional assessment, nutrition intervention strategies for pancreatic cancer patients, and the impact of nutrition intervention on the efficacy and adverse reactions of radiochemotherapy in pancreatic cancer patients.