Intracranial arachnoid cyst is a benign non-genetic cystic occupancy in which the cystic fluid has the same or similar properties as the cerebrospinal fluid. They are classified as congenital and acquired arachnoid cysts. Most patients have no clinical symptoms. They can occur at any age and are more common in children. Arachnoid cysts are common singly or in multiple cases. The most common site is the temporal fossa, followed by the posterior cranial fossa, suprasellar pool, cerebral convexity, tetrasellar pool, and interhemispheric fissure. The clinical manifestations of arachnoid cysts vary depending on the location, size, and compression of the surrounding brain tissue. Most can be asymptomatic, while a few have sudden onset due to minor trauma resulting in cyst rupture or even hemorrhage. The stimulating symptoms are seizures (with high frequency of seizures in temporal fossa and cerebral convexity); suprasellar pool cysts can cause pituitary dysfunction with precocious puberty and reduced growth hormone. Posterior cranial fossa cysts can cause trunk ataxia and unstable walking; pontocerebellar horn cysts can cause cranial nerve dysfunction; cysts blocking the cerebral fluid circulation pathway can produce symptoms of high cranial pressure. Cranial CT or magnetic resonance examination can clarify the diagnosis. Treatment of intracranial arachnoid cysts: asymptomatic patients can be followed up and observed by regular review of cranial CT to observe changes in cyst volume. Symptomatic treatment can be given for general symptoms. For occasional seizures, antiepileptic treatment can be given. For patients with frequent seizures, gradually increasing cysts, hydrocephalus, cysts larger than 20 ml in volume, or cysts causing local skull augmentation and thinning, surgical treatment should be used. Surgical procedures: craniotomy, cyst-abdominal shunt, intracystic shunt, neuroendoscopic fistulotomy, etc.