The treatment of extensive subarachnoid hemorrhage includes general treatment, symptomatic treatment, lowering intracranial pressure, prevention and treatment of rebleeding, prevention and treatment of cerebral vascular contracture, prevention and treatment of hydrocephalus and so on. 1. General treatment: bed rest, avoiding emotional excitement and exertion, abstaining from smoking and alcohol. 2. Symptomatic treatment: sedative drugs, such as diazepam, can be used for those who are irritable. Those with high fever can be physically cooled down, and sodium valproate can be used when seizures occur. 3. Reduce intracranial pressure: Limit fluid intake, use mannitol, furosemide, etc. to reduce intracranial pressure. 4. Prevention and treatment of rebleeding (1) Regulate blood pressure: calcium channel blockers such as nimodipine can be used to control the systolic blood pressure below 160mmHg. (2) Antifibrinolytic drugs: such as 6-aminohexanoic acid to reduce the risk of rebleeding. (3) Surgery or interventional therapy: surgical clamping or interventional embolization of the aneurysm can be performed to prevent rebleeding. 5. Prevention and treatment of cerebral vascular contracture (1) Maintaining blood volume: avoid excessive dehydration and rehydrate when necessary. (2) Early use of calcium channel blockers: such as nimodipine. (3) Early surgery or intervention: prevent cerebral arterial spasm by removing the aneurysm, removing the blood clot, and preventing the blood clot from releasing arterial spasm-causing substances. 6. Prevention and treatment of hydrocephalus (1) Drug therapy: e.g. acetazolamide, mannitol, etc. (2) External drainage of cerebrospinal fluid by ventricular puncture: it can reduce cranial pressure and improve symptoms. (3) Cerebrospinal fluid shunt: including ventriculo-atrial or ventriculo-abdominal shunt. Patients with extensive subarachnoid hemorrhage should go to the hospital in time and receive standardized treatment under the guidance of doctors.