Head and neck tumors lack typical characteristics in the early stage, often progressing to middle to advanced stages when obvious symptoms emerge. Radiotherapy and chemotherapy are often employed as adjuvant treatment. However, the risk of oral mucositis (OM) is relatively high after the therapies, especially for elderly patients, whose treatment tolerance is weakened, rendering them more susceptible to OM and subsequent manifestations including dysphagia and pain that compromise the intake of nutrients. Timely identification of the risk factors for OM and exploration of preventive strategies are of great significance for reducing the occurrence of OM in this population. In this article, we review the risk factors and preventive measures of OM in elderly patients with head and neck cancer after radiotherapy and chemotherapy, providing a reference for the prevention and treatment of OM.