Objective To explore the effect of protein intake on the nutritional status, body compositionp and quality of life ofpatients with head and neck cancer treated by radiotherapy. MethodsThe patient-generated subjective global assessment method was adopted to evaluate the nutritional status of 83 patients with head and neck cancer before and after radiotherapy. Nutrition interventions (dietary guidance, ONS, PN) were also totally employed during their therapy. According to theiractual protein intake, these patients were divided into two groups, group A [≥0.8g/(kg·d)] and group B [<0.8g/(kg·d)]. The status of nutrition, assessment of body composition and quality of life before and after radiotherapy in two groups of patients were compared. ResultsThe incidence of malnutrition in two groups had no statistic difference before radiotherapy (P≥0.5). After radiotherapy, the incidence of malnutrition and the change of the grip force in A group were significantly lower than that in B group (P<0.05); Changes in body composition in A group were significantly lower than in B group, such as body weight, percentage change in body weight, BMI, percentage of fat body mass change, fat-free mass change, muscle mass change, and FFMI index (P<0.05); The quality of life scores in two groups had no statistic differencebefore radiotherapy; after the radiotherapy the changes of fatigue, insomnia, loss of appetite, pain, the overall quality of life in group A are better than in group B (P<0.05). ConclusionNutritional interventions can effectively maintain the nutritional status, improve continuously the physical strength and the quality of life in head and neck cancer patients with radiotherapy.