Aquaporin4 (AQP4), a waterchannel protein, is highly expressed in the brain, which is important elements in the formation of brain edema and plays an important role in the rapid transmembrane transport.AQP4 expression upregulates after ischemiareperfusion injury in rats, making the astrocytic endfeet swelling, with the consequence of the injury of bloodbrain barrier(BBB), increasing the permeability of BBB, render too much water in the blood flow to the brain parenchyma, which results in cytotoxic edema, disordering the stability of the central nervous system.In addintion, the increased permeability of BBB is one of the important reasons for the cerebral stroke, therefore, it is essential that research the relationship between AQP4 with BBB further and restore the bloodbrain barrier injury bea new strategy for the prevention and treatment of stroke, worthy of further research.