Background The discovery of ischemic penumbra provides theoretical support for the necessity of thrombolytic therapy after cerebral infarction. However, with the restoration of perfusion, a series of complex mechanisms exist in the process that the injured brain tissues in ischemic penumbra gradually resume their normal function.Objective To explore the developmental process of ischemic penumbra，and to put forward the new ideas of saving the survived cells in ischemic penumbra.Content This article reviews the relationship between the damaging mechanisms and the protective mechanisms in ischemic penumbra after cerebral infarction. Trend It will become particularly important to save the injured brain tissue on the basis of maximizing the endogenous protective mechanism after cerebral infarction.