Abstract: Objective To evaluate the application of the Patient Generated Subjective Global Assessment (PG-SGA) scale on nasopharyngeal carcinoma (NPC) patients with chemoradiotherapy. Methods A total of 60 NPC patients who received concurrent chemoradiotherapy from September 2019 to November 2020 were selected. They were randomly divided into two groups: a control group and an experimental group. The experimental group was assessed by PG-SGA scale,and individualized enhanced nutrition counseling and oral nutritious supplements were prescribed to the patients with grade B≥2. Patients in the control group were given routine nutritional counseling and oral nutritional supplementation. Both groups were compared for body weight index (BMI), Alb and Hb at admission, after radiotherapy for 20 times, and at the end of radiotherapy. Meanwhile, the acute radiological toxic and side effects were recorded at the end of radiology. Results Before radiotherapy, there were no statistical differences in PG-SGA score, BMI, Alb and Hb between the two groups (P>0.05). After radiotherapy for 20 times and at the end of radiotherapy, both groups presented increases in PG-SGA scores, decreases in BMI and decreases in Alb and Hb, where the experimental group has better results than the control group (P＜0.05). There was no statistical difference in the score of xerostomia between the two groups at the end of radiotherapy (P＞0.05), and the scores of radiation dermatitis and oral mucositis of patients in the experimental group were lower than those of the control group (P＜0.05). Conclusions Nutritional intervention assessed by PG-SGA can significantly reduce the acute radiation toxicity and improve the nutritional condition, quality of life and treatment compliance of NPC patients during chemoradiotherapy.