Objective: To review the recent overseas research about the basic principle of perfusion-weighted imaging (PWI) and the prediction and evaluation of stroke episode. Data sources: An online search of Medline database was undertaken to identify the related articles about PWI and application on stroke between 1990 and 2005 using the keywords of "perfusion-weighted imaging, Stroke", "cerebral perfusion, stroke" and "cerebral blood flow", and language was limited to English. Study selection: All the articles were checked primarily, and those relevant to PWI and application on stroke were selected while those not obviously unrandomized clinical trials were excluded, and the full texts of rest were looked up. Inclusive criteria: randomized clinical trial (RCT), whether it was single-blind method, double-blind method or non-blind method. Data extraction: Totally 21 related articles were collected, and 6 repeated articles were excluded. Finally the rest 15 articles were reviewed. Data synthesis: Of the 15 articles accorded with the criteria, there were 91 cases. The articles reviewed the fundamental principle of PWI on views of basic technology, type of contract medium, stage of cerebral ischemia after stroke, common parameters and significance of PWI, and explained the application of PWI in cerebral infarction from the change of cerebral blood flow after stroke, development of predicting cerebral ischemia and anoxia, evaluation of cerebral infarction scope and prognosis judgement, etc. Conclusion: PWI can be used to study the change of cerebral blood flow after stroke, provide the essential blood dynamical parameters as well as evaluate the volume of final infarction and judge the disease prognosis of stroke.