Microglia are the principal immune effectors in brain and participate in a series of neurodegenerative diseases.  The microglial shapes are highly plastic.  The morphology is closely related with their activation status and biological functions.  Cerebral ischemia could induce microglial activation, and microglial activation is subjected to precise regulation.  Microglia could play either protective or neurotoxic roles in cerebral ischemia.  Therefore, regulating the expression of receptors or protein molecules on microglia, inhibiting the excessive activation of microglia and production of pro-inflammatory factors, promoting the release of neuroprotective substances might be beneficial to the treatment of cerebral ischemia.  The study about relationship between microglia and cerebral ischemia will shed a light on the treatment of cerebral ischemia.  This paper is a review of microglial activation and regulation during cerebral ischemia as well as related therapeutic methods.