Abstract: Dysphagia is the common adverse reaction after the radiotherapy for head and neck tumors. More than 76% of patients with head and neck cancer who received chemoradiotherapy had difficulty swallowing. The life quality of patients with mild dysphagia will be affected, while patients with severe symptoms may suffer from life danger. The existence of dysphagia is related to the tumor status, treatment methods, rehabilitation means and so on. Its prevention and treatment are the key to ensure the quality of life of patients with head and neck cancer. However, the current clinical prevention and treatment methods are obviously insufficient. This paper researches the anatomical and physiological process of swallowing system and the causes of the formation of dysphagia in head and neck tumors, and makes a review on the influence of radiotherapy on its developmental process, the evaluation of dysphagia and the prevention measures such as the training of swallowing functions in order to provide more thoughts on further preventing the appearance of dysphagia.