Objective To study MRI characteristics and value in the diagnosis of nasopharyngeal carcinoma with skull base erosion. Methods 86 cases of nasopharygeal carcinoma with positive nasopharyngeal pathology and symptoms of skull base erosion were selected. Axial T1WI, T2WI and coronal, sagital T1WI were performed. 47 cases had axial, coronal and sagital T1WI examination post Gd-DTPA injection. Results Areas of skull base involvement were as follow: 56 cases with pterygoid process, 54 with clivus, 28 with foramen ovale (including sphenoid wing), 27 with petrous apex, 1 with occiptal bone. 71 cases had more than one area involvement. There are four patterns in our group: ①Defect in the signal avoid cortex of skull base; ②High signal intensity of marrow was replaced by tumor; ③Contrast enhancement in abnormal bone; ④String like enhancement passing nerve foramen in skull base. 44 cases included intracranial abnormal. Conclusion MRI is the preferred technique in dementstrating skull base involvemetn of nasopharyngeal carcinoman.