Objective To explore the effect of individualized nutritional intervention based on dietary energy on the radiotherapy tolerance, nutritional status and quality of life of patients with postoperative radiotherapy for thyroid cancer. Method 98 patients with postoperative radiotherapy for thyroid cancer treated in Qinhuangdao First Hospital from January 2018 to June 2020 were selected as the research objects. According to the filing order of admission, patients were divided into control group and observation group, 49 patients each. From radiotherapy, the control group was given routine nutrition intervention, and the observation group was given individualized nutrition intervention based on dietary energy supply for 4 weeks. The body mass, upper arm muscle circumference and skinfold thickness, radiation tolerance, nutritional status [serum albumin (SA), prealbumin (PA), transferrin (TF)] before and after intervention, cancer⁃related fatigue, quality of life (FLIC) and nutritional diet compliance were compared between the two groups. Result After the intervention, the body weight, upper arm muscle circumference and skinfold thickness of the observation group were higher than those of the control group (P<0.05); after the intervention, the observation group had PA (350.47±52.32) mg/L, SA (35.48±2.01) g/L, TF (2.26±0.54) g/L are higher than the control group (321.48±42.32) mg/L, (31.12±2.86) g/L, (1.90±0.50) g/L (P<0.05); the radiotherapy tolerance of the observation group was higher than that of the control group (P<0.05); the degree of cancer⁃related fatigue in the observation group (no fatigue or mild fatigue 48.98%, moderate fatigue 30.61%, severe fatigue 20.41%) was low In the control group (26.53%, 36.73%, 36.73%) (P<0.05); the FLIC score of the observation group after intervention was higher than that of the control group (P<0.05); the nutrition diet compliance of the observation group was higher than that of the control group (P<0.05). Conclusion Individualized nutritional intervention based on dietary energy can help improve the nutritional status of patients undergoing radiotherapy for thyroid cancer, maintain their body mass, reduce cancer⁃related fatigue, enhance radiotherapy tolerance, and improve the quality of life.