1.The most common cause of spontaneous subarachnoid hemorrhage (SAH), examination and treatment purpose Spontaneous subarachnoid hemorrhage is caused by rupture of aneurysm in about 80%-85% of cases, which is the most common cause, followed by intracranial arteriovenous malformation. Before CT/MRI examination, the diagnosis of SAH was mainly based on lumbar puncture. However, with the rapid development of imaging and the high intracranial pressure after hemorrhage, lumbar puncture should be done with caution! The gold standard for the etiological diagnosis of spontaneous SAH is whole brain angiography (DSA). The aim of treatment of spontaneous SAH is to prevent and control re-bleeding, so it is especially important to clarify the cause of bleeding and treat it. Yin Hao, Department of Neurosurgery, People’s Hospital of Guizhou Province, China 2. Identification of spontaneous cerebral hemorrhage and hypertensive cerebral hemorrhage For the hemorrhage site is atypical, such as not in the basal ganglia area but in the lateral fissure area, suprasellar pool, longitudinal fissure pool, motor area, etc. or repeated hemorrhage, without clear history of hypertension, we should be highly alert to whether it is a ruptured aneurysm or cerebrovascular malformation hemorrhage, and further investigate to avoid misdiagnosis and mistreatment, which may lead to disastrous consequences. 3.The main diagnosis and treatment scope of cerebrovascular disease group is the etiology of spontaneous subarachnoid hemorrhage; the diagnosis and treatment of intracranial aneurysm; the diagnosis and treatment of intracranial/vertebral vascular malformation; arteriovenous fistula, internal carotid artery cavernous sinus fistula, dural arteriovenous fistula; refractory cerebral ischemic diseases such as carotid endothelial plaque formation leading to stenosis can be treated by carotid endothelial debridement; anomalous vascular network disease at the base of the brain (smog, Moyamoya disease). Moyamoya disease); preoperative embolization of vascular-rich tumors, etc.