Cerebral vasospasm is a constriction of cerebral blood vessels, which often occurs in subarachnoid hemorrhage, craniocerebral injury, craniotomy and endovascular interventions, etc. The persistent spasm and constriction of cerebral blood vessels may lead to ischemia of the corresponding brain tissue and neurological deficits, which is a serious hazard. The main cause of cerebral vasospasm is subarachnoid hemorrhage, the blood flowing into the subarachnoid cavity and its degradation products stimulate the blood vessels and lead to cerebral vasospasm, once the diagnosis of subarachnoid hemorrhage is confirmed, cerebral angiography should be performed to clarify the cause of subarachnoid hemorrhage, subarachnoid hemorrhage is often caused by intracranial aneurysm rupture, depending on the patient’s condition, craniotomy and aneurysm clamping surgery or endovascular intervention embolization treatment should be performed as soon as possible. The subarachnoid hemorrhage is often caused by ruptured intracranial aneurysm. During craniocerebral injury and surgery or endovascular intervention, the injury to the blood vessels, the mechanical stimulation during the endovascular operation, the chemical substances such as contrast agents and the bleeding into the subarachnoid space during the operation can lead to cerebral vasospasm. Therefore, during cranial surgery and endovascular interventions, local vascular irritation and injury should be minimized and intraoperative bleeding should be avoided to induce cerebral vasospasm. Other conditions may also trigger cerebral vasospasm, such as tuberculous and septic meningitis, migraine, and hypertensive encephalopathy. In conclusion, many causes may lead to cerebral vasospasm, and early prevention, early diagnosis and early treatment are the keys to reduce the occurrence of cerebral vasospasm and improve the prognosis.