In general, radiotherapy patients should replenish the nutrients needed by the body, improve immunity, and take good care of the corresponding parts of the body for radiotherapy. If it is head and neck cancer, radiotherapy may lead to radioactive oral mucositis, patients should eat well-digested and soft food to protect oral mucosa and avoid spicy and stimulating food. If it is esophageal cancer, radiotherapy may lead to radioactive esophagitis, high protein, high nutrition, soft and not hard food should be chosen. If it is gastric cancer, patients should consume well-digested food, do not eat fried and hard food. If it is pancreatic cancer patients should choose high quality protein to maintain nutrition. Radiotherapy patients should supplement protein, eat more eggs, milk, fish, lean meat, etc. to replenish energy and enhance immunity, and pay attention to the protection of radiotherapy site.