Intracranial aneurysm is a limited dilatation of the arterial wall caused by congenital or acquired pathological changes that result in outward protrusion. It has an insidious course, sudden onset, and high mortality rate. 8-32% of patients die after the first subarachnoid hemorrhage (SAH), and the mortality rate is more than 60% within 1 year and more than 85% within 2 years. Aneurysms occur in middle-aged people (30-60 years old) and are slightly more common in women than in men (1.34:1). The main causes of aneurysms are congenital vascular defects, vascular inflammation, atherosclerosis, atherosclerosis, hypertension, etc. The most common site is the internal carotid artery. The internal carotid artery is the most common site of occurrence, followed by the anterior communicating artery, middle cerebral artery aneurysm, anterior cerebral artery aneurysm, and vertebral-basilar artery aneurysm, which is less common. Aneurysms are classified according to their diameters: small aneurysms (diameter <5mm); general aneurysms (5mm≤diameter <15mm); large aneurysms (15mm≤diameter <25mm); and giant aneurysms (diameter ≥25mm). According to the clinicopathological morphology: cystic aneurysm; systolic aneurysm; entrapment aneurysm; pseudoaneurysm. Typical symptoms: sudden severe headache, about 97%, accompanied by vomiting and impaired consciousness, severe cases can be coma, respiratory arrest, neck and waist pain. It may be accompanied by limited cerebral nerve dysfunction. Auxiliary examination 1, lumbar puncture: it is the most sensitive examination method for SAH, which can measure the intracranial pressure, color of cerebrospinal fluid, blood concentration, cell count, and protein content of cerebrospinal fluid in the later stage. 2, CT examination: cranial CT is mainly used for the diagnosis of SAH, and it is the first choice, CT can clarify the amount of hemorrhage, hemorrhage site, the possible location of aneurysm, the acute dilatation of ventricles, cerebral infarction caused by cerebral vasospasm, etc. CTA, especially 3D-CTA, is of great reference value for the diagnosis of cerebral aneurysm, and it can be used as the first choice in case of emergencies. It can clearly show the location and size of aneurysm. MRA: It can be used as the first choice of non-invasive examination for aneurysm diagnosis, and can show aneurysms with a diameter of more than 3mm. It can show aneurysms over 3mm in diameter, and is comparable to CTA and DSA, providing the possibility of non-invasive diagnosis and follow-up diagnosis. 4.Digital subtraction cerebral angiography (DSA): DSA is the "gold standard" for diagnosing intracranial aneurysms. It can show 0.5mm cerebral blood vessels, and only a very small number of patients can be attributed to unexplained SAH, and it can also show vasospasm and lumen narrowing, etc. Its diagnostic accuracy is more than 95%, and its follow-up is possible. Its diagnostic accuracy is more than 95%, which is a kind of inspection technology that cannot be replaced by any kind of imaging. In particular, 3D-DSA has a sensitivity of 97.2% and a specificity of 100% for aneurysms. Treatment: The best treatment for intracranial aneurysm is still surgical clamping of the aneurysm neck, as well as aneurysm wrapping or reinforcement surgery, isolation surgery and so on. In recent years, endovascular embolization of the aneurysm cavity has received more and more attention. The catheter is directly placed into the aneurysm cavity, and the aneurysm cavity is filled with various materials to achieve the purpose of occluding the aneurysm. The choice of interventional technique should be selected for aneurysms that are difficult to surgically clamp or failed to clamp, elderly, poor health, other diseases that cannot tolerate surgery, wide neck aneurysms, complex aneurysms (such as posterior circulation aneurysms, shuttle aneurysms, giant aneurysms, etc.), laminated aneurysms and pseudoaneurysms.