The occurrence proliferation invasion and metastasis of malignant tumors are closely related to the nutrients in the tumor microenvironment. The nutritional composition of tumor microenvironment is affected by the dietary composition of tumor organism. Metabolic reprogramming is one of the main characteristics of tumor cells. Tumor cells can adapt to an unregulated state of cell proliferation by upregulating the absorption and synthesis of nutrients such as glucose amino acids and fats. Tumor dietary modification is to change the dietary pattern to achieve direct or synergistic tumor treatment. There are various ways to modificate diet which can be achieved by adjusting the total energy / energy composition ratio of the diet or limiting eating time or by increasing or decreasing the content of a specific nutrient in the diet. Although multiple dietary modifications have shown significant synergistic effects with radiotherapy in many preclinical and some clinical studies there is still no clear expert consensus or guideline to recommend the best dietary modification mode for cancer patients receiving radiotherapy due to the lack of large-scale clinical research. This paper systematically reviews the studies on several commonly used dietary patterns such as conventional balanced diet intermittent fasting calorie restriction diet ketogenic diet and caloric restriction ketogenic diet in patients with tumor radiotherapy and expounds the advantages and limitations of different dietary patterns for tumor radiotherapy hoping to provide certain reference for the research and clinical application of dietary regulation combined with radiotherapy.