The number of years a patient with arachnoid cyst can live depends mainly on the specific condition and cannot be generalized. Arachnoid cysts are benign intracranial tumors, mostly associated with congenital developmental abnormalities, trauma, and inflammation, and are classified into two conditions: symptomatic and asymptomatic. In the case of asymptomatic arachnoid cysts, the occupancy is usually small and the cranial brain is not compressed, so treatment is usually not necessary and regular observation is sufficient, and patients can survive for a long time without affecting their life expectancy. If an arachnoid cyst compresses brain tissue, causing a series of symptoms such as headache, dizziness, nausea, vomiting, numbness and weakness of limbs, slurred speech, etc., and the arachnoid cyst is growing, complications may also arise that can affect the patient’s survival, such as causing obstruction of cerebrospinal fluid circulation pathways, resulting in acute hydrocephalus, which may lead to death within a day. Patients with arachnoid cysts can be temporarily treated with observation and conservative treatment, and once they develop significant clinical symptoms and related complications, they need to actively cooperate with their doctors for treatment.