Objective:To study the clinical features and prognostic factors of brain injury after radiothera-py for nasopharyngeal carcinoma(NPC).Methods:From January 1998 to June 2006,49 NPC patients with Dost-radiation brain injury in our hospital were analyzed retrospectively.Results:The incidence of post-radia-tion brain injury after single-pass radiotherapy and re-course radiotherapy was 2.31%and 9.64%.respectively ,(P＜0.05).The median latency period was 50.5 months for single-pass radiotherapy and 25.5 months for re-course radiotherapy.Fourty-nine patients suffered from radiation injury in the brain.The lesions were locat-ed in the temporal lobe in 37 patients(75.5%),in the pens in 9 patients(18.4%)and in mixed position in 3 pa-tients(6.1%).The symptoms and signs of the patients could be alleviated by therapy, but the quality of life was not improved.Conclusion:Radiation brain injury in NPC patients after radiotherapy is related to field de-sign.The incidence of radiation brain injury in the temporal lobe is the highest.Compared with single-pass ra-diotherapy, re-course radiotherapy leads to higher incidence of brain injury and shorter latency period.