Cerebral vasospasm is considered as the main cause of delayed cerebral ischemia after aneurysmal subarachnoid hemorrhage. Its pathogenesis is not clear yet， and its curative effect is not good. Recent studies have demonstrated that cerebral vasospasm following subarachnoid hemorrhage is influenced by many factors， including cerebral vascular dysfunction， oxidative stress， cortical depolarization， immune response， and so on. This is to review the possible pathogenesis and prevention and treatment of cerebral vasospasm after subarachnoid hemorrhage.