Abstract: Objective: To discuss MRI manifestation on the nasopharyngeal carcinoma (NPC) and neoplasm metastasis of nasopharyngeal carcinoma located at the base of skull and to evaluate the radiotherapy on it at the middle process and the end process. MRI could provide protect to the clinical treatment and to the patient. Methods: Thirty NPC patients were collectible into this study, all the patients were examined through MRI imaging and with Gd-DTPAenhancement at the middle process and the end process of radiotherapy. the patient who was at the status that the neoplasm without the biological activity after the radiotherapy might be examined again at 3-6 month after the end process of radiotherapy. Results: In the thirty patients of the NPC, 11cases with the neoplasm metastasis located at the base of skull.after the radiotherapy,21 cases were at the status that the neoplasm without the biological activity,2 cases of neoplasm were in the liquid necrosis status, 6 cases of the neoplasm were in the status of coagulability necrosis (the status of fibroglia), after the radiotherapy, the neoplasm of 9 cases still had the biological activity. Conclusion: MR imaging with Gd-DTPA enhancement was very useful to the diagnosis of NPC and neoplasm metastasis of nasopharyngeal carcinoma located at the base of skull and to evaluate the effect of radiotherapy.