Intracranial aneurysms are mostly abnormal bulges in the walls of intracranial arteries and are the first cause of subarachnoid hemorrhage, ranking third after cerebral thrombosis and hypertensive cerebral hemorrhage among cerebrovascular accidents. It can develop at any age, mostly in middle-aged and elderly women between 40 and 60 years old. Most scholars believe that intracranial aneurysms are caused by local congenital defects in the walls of intracranial arteries and increased intraluminal pressure, and that hypertension, cerebral atherosclerosis, and vasculitis are related to the occurrence and development of aneurysms. Intracranial aneurysms are most likely to occur in the arterial ring at the base of the brain (Willis ring), with 80% of them occurring in the anterior half of the arterial ring at the base of the brain. Small, unruptured aneurysms are asymptomatic. Symptoms of intracranial aneurysms are divided into three categories: 1. intracranial hemorrhage: most patients have simple subarachnoid hemorrhage, manifested as sudden headache, vomiting, impaired consciousness, epileptic-like seizures and meningeal irritation signs. 2, focal symptoms: large aneurysms often produce compression symptoms, hemiparesis, actinic nerve palsy and obstructive hydrocephalus. 3. Cerebral ischemia and cerebral artery spasm: patients may have different degrees of neurological dysfunction, hemiparesis, aphasia, profound and superficial sensory loss, blindness, and psychiatric symptoms. Cerebral angiography is required to confirm the diagnosis of intracranial aneurysm. Cerebral angiography should be performed in any patient with subarachnoid hemorrhage, spontaneous III-IV cranial nerve palsy or posterior group cranial nerve disorder.