The lack of a piece of skull in the head will have an impact on health, the skull defect in life is caused by a variety of factors, such as: car accidents, mechanical injuries, falling objects, diseases and so on. Once skull defect brings great harm to patients’ health and psychology, because long-term skull defect will cause concavity or bump in some patients, and cause various complications to seriously threaten patients’ health, and also affect patients’ beauty and bring trauma to patients’ psychology. Some patients with cranial defects are reluctant to make cranial bone repair, feeling that there is no need to do it because the site of cranial defects is not big, and they do not understand what are the effects of cranial bone loss. When the intracranial soft tissue loses the protection of bone flap, its restriction also disappears, the cerebral venous return and the external pressure on the dural sinus decrease, the brain parenchyma can expand outward, resulting in the increase of venous return of cerebral hemispheres and the increase of extracellular fluid absorption such as plasma and tissue fluid, thus causing the volume of brain parenchyma cells to decrease, the space in the brain increases and the ventricle expands, thus developing into hydrocephalus. Hydrocephalus can cause great damage to the patient’s life safety and central nervous system, and in severe cases, the patient can fall into coma. Therefore, when the skull defect is stabilized, the patient must undergo skull repair surgery.