Abstract: Early brain injury (EBI) in spontaneous subarachnoid hemorrhage (SAH) plays an important role in prognosis and it become a key target period for clinical treatment and basic research. There were many pathophysiological change in the first few minutes after intracranial aneurysm ruptured. These include increased intracranial pressure (ICP) followed by in⁃ tracranial circulation disorders, calcium overload and sodium, magnesium level fluctuation, ion steady-state disorders in mi⁃ croenviroment of brain cells, serious brain edema due to blood brain barrier (BBB) damage, and changes in other molecules levels, all of which will aggravate SAH. EBI in SAH is one of the important factor that leads to poor prognosis. With the ad⁃ vancement of understanding its pathogenesis, new approach would be available to treat SAH in clinic.

Key words: subarachnoid hemorrhage, intracranial aneurysm, brain injuries, vasospasm, intracranial, review