Submicrocephalic herniation combined with spinal cord cavitation (Chiari malformation) is a common neurosurgical condition that causes damage to the spinal cord due to the formation of spinal cord cavities, resulting in sensory-motor dysfunction of the limbs, severely reducing the quality of life of the patient and even causing disability. At present, surgery is the only effective way to treat subungual herniation of the cerebellum, and many patients have fear of surgery and doubts about its efficacy. For this reason, we explain the rationale and efficacy of surgical treatment to our patients by combining the preoperative and postoperative findings of some cases. A herniation of the cerebellar tonsils out of the inferior border of the greater occipital foramen by 5 mm is diagnosed as a subcerebellar tonsillar herniation. Normally, there is good cerebrospinal fluid circulation in the region of the foramen magnum, and cerebrospinal fluid can flow freely in the cranial cavity and spinal canal. In the presence of a subcerebellar tonsillar herniation, the cerebellar tonsils block the cerebrospinal fluid circulation in the region of the foramen magnum. This leads to the formation of a spinal cord cavity, which destroys the spinal nerve fibers and leads to sensory and motor dysfunction and even muscle atrophy in severe cases. Therefore, the key to the treatment of this disease is to relieve the compression of the spinal cord by the cerebellar tonsils in the greater occipital foramen and to re-establish the cerebrospinal fluid circulation in the region of the greater occipital foramen. The conventional treatment is a posterior cranial fossa decompression-occipital foraminoplasty. This is a surgical skin incision that is usually only 2-3 cm long. The following are the preoperative and postoperative MRI examinations of some patients: Case 1: Zhang, male, 16 years old, with occipital pain, bilateral upper extremity numbness for 2 years, bilateral upper extremity weakness, and muscle atrophy for 1 year. Preoperatively, the spinal cord cavity was visible; postoperatively, the spinal cord cavity was reduced Case 2: Li, female, 45 years old, with bilateral upper extremity numbness for 5 years, and the right upper extremity was heavy. Before surgery; 3 months after surgery, the cavity was reduced; 1 year after surgery, the cavity disappeared Conclusion: posterior cranial fossa decompression-occipital pooloplasty is an effective way to treat cerebellar submandibular herniation spinal cavernous disease.