Occipital greater pool cyst, also known as occipital greater pool arachnoid cyst, is a common intracranial lesion. If it does not cause symptoms such as hydrocephalus and increased intracranial pressure, it can be observed for a long time. Some of the occipital pool cysts can cause hydrocephalus, and patients have headache and other symptoms; or the cysts can compress the cerebellum and affect cerebellar development, requiring surgery. Do ordinary CT or MRI reported as giant occipital pool, or occipital pool cyst. Further tests should be done before surgery, especially magnetic resonance water imaging and cerebrospinal fluid films, both of which help to identify giant occipital pool and occipital pool arachnoid cysts. Generally speaking, there are 3 surgical procedures to treat occipital pool cysts: 1. Suboccipital craniotomy of the cyst wall: part of the cyst wall is removed and the fourth ventricle is opened, so that the fourth ventricle, the cyst and the occipital pool are connected to relieve hydrocephalus. Because of the large trauma, adhesions often occur at the outlet of the fourth ventricle after surgery, leading to severe non-traffic hydrocephalus. In addition, there are many patients who experience regeneration of the cyst wall and recurrence of cyst closure. At present, this procedure is gradually eliminated. 2.Cyst-abdominal shunt: craniotomy or drilling under the occiput, inserting the shunt tube into the cyst, and placing the other end into the abdominal cavity through the subcutaneous tunnel to continuously drain the cystic fluid into the abdominal cavity. This procedure is less invasive and easier to perform, but the patient needs to carry the tube for life and keep it open. In addition, because the shunt pressure is fixed and the drainage lobe is mostly cerebrospinal fluid, it will destroy the self-regulation function of cerebrospinal fluid circulation, and once the shunt is blocked, severe headache, vomiting, blindness, and even sudden death can occur. At present, more patients are treated by this surgery, and the postoperative risk is higher. 3, endoscopic surgery: including two surgical methods, suboccipital craniotomy endoscopic partial cyst wall resection + cyst-ventricular-ventricular pool fistula, frontal craniotomy endoscopic third ventricular base fistula. It has the characteristics of small trauma and good efficacy, but requires high requirements for hospitals and surgeons. The hospital should have neuroendoscopic equipment and the surgeon needs to master neuroendoscopic surgery techniques. The procedure is currently being promoted.