Subarachnoid hemorrhage is an acute hemorrhagic cerebrovascular disease caused by the rupture of blood vessels at the base of the brain due to various etiologies. The most common clinical cause of subarachnoid hemorrhage is trauma, also known as traumatic subarachnoid hemorrhage. For subarachnoid hemorrhage that is not due to trauma but is caused by a cerebral vascular lesion that flows directly into the subarachnoid space, also known as spontaneous subarachnoid hemorrhage, this type of lesion usually requires further treatment to identify the cause. Spontaneous subarachnoid hemorrhage accounts for about 10% of acute strokes and 20% of hemorrhagic strokes. It ranks third after cerebral thrombosis and hypertensive cerebral hemorrhage among cerebrovascular accidents. The etiology of spontaneous subarachnoid hemorrhage includes intracranial aneurysm, arteriovenous malformation, dural arteriovenous fistula, hypertensive arteriosclerosis, anomalous vascular network at the base of the brain (moya-moya disease) and hematologic disease, but intracranial aneurysm is the most common. The clinical manifestations of subarachnoid hemorrhage are mostly severe headache with rapid onset, as if the head is about to split open. In about 1/3 of patients, the aneurysm ruptures and death occurs before diagnosis and treatment. In 1/3 of the surviving cases, rebleeding may occur, mostly within 2 weeks after the first bleeding, with a higher mortality rate. In the acute phase of bleeding, the positive string of SAH confirmed by CT is extremely high, which is safe, rapid and reliable. After a week of hemorrhage, CT is not easy to diagnose because of the absorption of hemorrhage, and the diagnosis can be confirmed by lumbar puncture when yellowing cerebrospinal fluid is seen. Once the diagnosis of subarachnoid hemorrhage is confirmed, cerebral angiography should be performed to clarify the presence or absence of aneurysm and its exact location, morphology, internal diameter, number, and presence or absence of vasospasm to determine the surgical plan. Currently, for subarachnoid hemorrhage caused by aneurysm, Hunt-Hess classification is usually used: Grade I: no symptoms, or mild headache and cervical tonicity. Grade II: severe headache, neck tonicity, and no neurological symptoms other than cerebral nerve palsy such as the motoneurotic nerve. Grade III: Mild impaired consciousness, restlessness and mild cerebral symptoms. Grade IV: semi-coma, hemiparesis, early decerebrate tonicity and vegetative neurological deficits. Grade V: deep coma, decerebrate tonicity, and near-death state. Patients with disease below grade III should undergo early cerebral angiography and surgical treatment. Patients with disease above grade III can wait for further examination and treatment after stabilization. Currently, there are two clinical treatments for aneurysms, one is surgical clamping and the other is interventional embolization. Clamping surgery is the traditional treatment method, which has a history of more than 70 years, and the efficacy is relatively true, but the risk is high, and the operator needs to be familiar with intracranial anatomy, while the acute stage increases the risk and difficulty of the surgery due to cerebral edema and vasospasm, etc. Interventional treatment is a new technology that started in the 1990s, with less damage, faster recovery and lower complication rate, and with the development of material science and technology, it gradually With the development of materials and techniques, it has shown a tendency to replace surgery, especially in patients with acute hemorrhage because it can be operated without separating the brain tissue. The first subarachnoid hemorrhage may improve with medical treatment, but it is important to take the time to make fundamental treatment and not to wait and see, so as not to miss the opportunity and regret it. To get a reasonable diagnosis and treatment of this disease, it is necessary to have a hospital with an experienced specialist, remember.