Objective To summarize the experience in the diagnosis and treatment of undifferentiated pleomorphic sarcoma (UPS) induced by radiotherapy for adenoid cystic carcinoma of the nasal cavity and sinuses. Methods The clinical data of one patient with (UPS) induced by the 4-year postoperative radiotherapy for the adenoid cystic carcinoma of nasal cavity and paranasal sinus were retrospectively analyzed through combining with literatures. Results The patient accepted a nasal lateral incision for the majority of maxillary resection in January 2015, in which the tumor was completely excised; the result of postoperative pathological examination showed that it was adenoid cystic carcinoma of the left maxillary sinus, thus postoperative radiotherapy and chemotherapy were performed regularly. In December 2018, the patient was considered to have tumor recurrence, therefore, the left maxillary subtotal resection and nasal cavity and paranasal sinus tumor resection were performed, and the tumor was completely removed, the postoperative pathological result indicated that it was undifferentiated pleomorphic sarcoma. Conclusions Undifferentiated pleomorphic sarcoma is a rare heterogeneous solid tumor of low incidence, high malignancy and poor prognosis. Complete surgical resection of the tumor is still the most effective treatment for UPS. Multidisciplinary treatment for UPS has positive effect on prognosis.