The staging performance of MRI of cerebral infarction is firstly divided into six stages: there is the hyper-acute stage, usually within 1 hour of onset, the MRI flat scan is normal, and within 6 hours thickening of the cerebral gyrus and shallowing of the cerebral sulcus can be found. This is the performance of the hyperacute phase; in the acute phase is within 6-72 hours, when abnormal signal shadows in the brain can be found; in the 3-10 days of onset, abnormal signal shadows in the brain will appear and there will be occupying effects, such as midline shift, etc.; more than 10 days of onset, patients will have softening foci, and in the chronic phase, there will also be the performance of glial cell hyperplasia. Therefore, most patients with cerebral infarction should have DWI examination in the hyperacute stage to be able to detect the foci of high signal shadow of cerebral infarction early.