Objective To analyze the expression fractures of MRI and investigate the diagnostic value of functional magnetic resonance Imaging in central nervous system vasculitis(CNSV). Methods MRI appearance of 15 cases of CNSV proved by pathology or clinical treatment were retrospectively reviewed. Results 13 multiple cases distributed randomly and 2 cases solitary supratentorial lesions were found. Equal or slight hypointensity in 13 cases and mixed intensity in 2 cases on T1WI. Slight hyper or hyperintensity in 12 cases and mixed intensity in 3 cases on T2WI. Hyper-intensity in all cases on T2-flair. Hyper-intensity in 9 cases (6 cases with drop hypo-intensity), equal intensity in 3 cases and hypo-intensity in 3 cases on DWI. Hypo-intensity of micro-bleeding in 10 cases on SWI, including phlebectasis of homolateral lesions in 6 cases and contralateral lesion in 1 case. Slight hypo-perfusion in 7 cases and slight hyper-perfusion in 1 case among 8 perfusion cases. Most of lesions demonstrated piebald or gyrus enhancement. 2 cases of hyper-intensity lesions on T2WI were not enhanced. Thickened and obviously enhanced vessel wall in 9 cases, enhanced meningeal artery in 5 cases and enhanced peripheral cerebral pia mater of lesions in 4 cases. Beading blood vessel in 5 cases, middle cerebral artery occlusion similar to Moya-Moya disease in 1 case and normal blood vessel in 5 cases among 11 TOF-MRA cases. Beading blood vessel in 2 cases on 2 DSA cases, including 1 negative case on TOF-MRA. 7 cases of new lesions, 6 cases of advanced lesions and 2 cases of stable lesions were found before confirmed diagnosis of CNSV. 11 cases of obviously shrink or absorption lesions, 1 case of new lesion and 1 case of stable lesion were found with MR after impulsion hormonotherapy. Conclusion Characteristic expression of CNSV on MR is benefit to early diagnosis of CNSV and to guiding biopsy.