Abstract: Objective: To investigate the clinical value of MＲI diffusion weighted imaging( DWI) combined with 3D-TOF magnetic resonance angiography( MＲA) in the diagnosis of hyperacute massive cerebral infarction. Methods: Eighty-three cases with acute cerebral infarction were scanned using conventional MＲI，DWI sequence and 3D-TOF MＲA， the lesions in different sequence MＲI were compared and analyzed. Results: The T1WI and T2WI of 51 cases with onset time less than 2 h and 13 cases with onset time between 2 － 6 h were normal. The T2WI of 19 cases with onset time between 2 － 6 h were slightly high signal. All DWI were high signal. The artery stenosis and occlusion in 78 cases were found by 3D-TOF MＲA，which included 7 cases of internal carotid artery occlusion， 19 cases of middle cerebral artery occlusion and 10 cases of posterior cerebral artery occlusion. Conclusions: DWI can diagnose acute cerebral infarction and identify its location. DWI combined with 3D-TOF MＲA technology can quickly and accurately show the intracranial artery stenosis or occlusion and corresponding cerebral infarction.