Objective:To investigate the nutrition researches in radiation oncology, identify the hot topics, and inform the future development of radiotherapy nutrition.Method:Web of Science Core Collection was searched and Citespace-based analysis was performed for the bibliometric analysis of research papers on tumor radiotherapy nutrition.Results:A total of 1 243 articles were included, and there was an increasing trend in the annual number of articles published from 2014 to 2021. The top three countries with the most publications were the United States, China and Australia. In addition to radiotherapy, tumor and nutrition, common keywords in these articles included quality of life, weight loss, head and neck cancer, parenteral nutrition, enteral nutrition, and dietary intake.Conclusions:Domestic and foreign scholars have paid more and more attention to tumor radiotherapy nutrition. In recent years, the research hot topics are mainly head and neck tumors, nutritional support methods, concurrent chemoradiotherapy and patient prognosis. There was a scarcity of collaborations between domestic and foreign institutions. Institutions such as the State Key Laboratory in Oncology in South China, Sun Yat-sen University and Peking University have been continuously advancing the development of radiotherapy nutrition and have carried out a lot of researches. The gap between China and abroad is narrowing. Researches in China needs to be improved in terms of the depth and breadth. In the future, nutrition researches can further explore the aspects such as experimental protocol publication and the correlation of psychology and nutrition, strengthen international collaboration, and enhance international impact with high-quality publications.