Arachnoid cysts in the occipital pool are relatively common benign intracranial lesions, and most patients do not have any clinical symptoms, but are discovered accidentally during head trauma or cranial CT examinations during physical examinations. For asymptomatic arachnoid cysts in the greater occipital pool, no special treatment is needed, and periodic review and dynamic observation of cyst volume changes are sufficient. If the cyst is larger than 5 cm, the cyst may compress the cerebellar hemisphere and the fourth ventricle and cause obstructive hydrocephalus, and the patient may have headache, nausea, vomiting and other symptoms.