The etiology of right temporal subcranial plate arachnoid cyst is not yet clear, and may be related to congenital development, craniocerebral trauma, and intracranial infection. 1. Congenital development: the cyst is mainly formed by abnormal embryonic development, usually closely related to the subarachnoid space and brain pool. 2. Craniocerebral trauma: right temporal subcranial plate arachnoid cyst, also known as pseudoarachnoid cyst, may be due to the inflammatory reaction of the subarachnoid space caused by craniocerebral trauma. 3. Intracranial infection: This is also the cause of right temporal subcranial arachnoid cyst, which will form an inflammatory reaction in the subarachnoid space, which will lead to the pathological accumulation of cerebrospinal fluid, resulting in the formation of cysts, and the cyst wall can be seen in the inflammatory cells or ferritin deposits. Patients with right temporal subcranial arachnoid cysts should be given temporary observation or surgical treatment, depending on their condition, and should be followed up regularly.