Objective To explore longitudinal changes in nutrition related symptoms among head and neck cancer patients at different stages of radiotherapy, and to obtain optimal timing and protocols for the management of nutrition related symptoms. Methods A total of 111 head and neck cancer patients receiving radiotherapy were enrolled and surveyed with the Head and Neck Symptom Checklist. Results Nutrition related symptom with highest incidence rates in patients with head and neck cancer across the duration of radiotherapy was dry mouth (64.86%-96.40%), and symptom with the lowest incidence rate was diarrhea (0-5.41%). On the 1st, 3rd, 5th, and 7th week and 1 month into radiotherapy, the total severity scores were 3(2,8), 11(8,14), 14(11,19), 17(13,21), 9(7,13), points respectively, and the total interference scores were 2(1,4), 7(4,10), 10(7,13), 11(8,14), 6(4,8), points respectively, both severity and interference scores showing significant differences over time (P<0.01 for all). The symptom items of taste change severity, and interference on dietary intake had higher scores that other symptoms. Conclusion The incidence rate, severity and interference of nutrition related symptoms on dietary intake in patients with head and neck cancer aggravate as radiotherapy progresses. Taste change is the most serious symptom that interferes with dietary intake the most. Medical staff should pay attention to it and carry out symptom management as soon as possible.