Chiari malformation refers to the inferior cerebellar tonsils or both the inferior brainstem and the fourth ventricle, which protrude downward in a tongue-shaped manner and cross the foramen magnum to embed into the spinal canal. It is a congenital malformation of the craniocervical junction area. The pathology is characterized by herniation of the lower part of the cerebellar tonsils into the vertebral canal, extension, distortion and displacement of the pontine brain, medulla oblongata and fourth ventricle into the vertebral canal. Approximately 50% or more of this malformation is associated with spinal cord cavitation. Clinical manifestations may include chronic cranial hypertension, ataxia (manifested as cerebellar or spinal ataxia), pyramidal fasciculus, posterior group cranial nerve and upper cervical medullary spinal nerve palsy. A definitive diagnosis can be made with a craniocervical junction MRI. Once the diagnosis of Chiari malformation combined with spinal cord cavitation is made, hospitalization and surgery are required to control the progression of the disease and its serious consequences. Surgery is the mainstay of treatment for this malformation. There are several surgical approaches, and there is a lot of debate about the surgical approach and its efficacy. Some studies have shown that the prognosis of the open dura group is better than that of the unopened dura group, and the incidence of postoperative complications is lower in the dural repair group than in the unpatched dura group. Therefore, among many surgical treatment methods, posterior cranial fossa decompression + dural sac enlargement reconstruction is a more ideal procedure.