Objective To investigate the effects of nutritional therapy on nutritional status during the therapy of head and neck cancer patients, which were treated with platinum medication and chemoradiotherapy. Methods A total of 96 cases of head and neck cancer patients were randomly divided into a study group (n=48) and a control group (n=48). They were given nutritional intervention and conventional diet respectively during radiotherapy and chemotherapy. The nutritional status of the two groups were observed. The primary end point of this study was body weight changes, and the secondary indicators of this study included white blood cells, lymphocyte, albumin and other nutritional indicators. The statistics were analyzed by using SPSS software package. Results Both groups of patients showed different degrees of weight loss, bone marrow suppression and decreasing nutritional indicators during the treatment. The study group’s body weight loss (P=0.001), the reduction of white blood cells (P=0.009), lymphocytes (P=0.000), hemoglobin (P=0.033) and hypoproteinemia (P=0.010), the chances and severity of low calcium (P=0.020) and magnesium (P=0.006) were lower than the control group’s, these are with statistical differences. Moreover, in the study group, the proportion of the increase of the acute phase reactive protein was significantly lower than that of the control group (P=0.000). Conclusions Nutritional intervention can reduce the incidence of malnutrition in head and neck cancer during radiotherapy and chemotherapy. However whether it will lead to long-term survival benefits, further studies are needed.