The skull is the hard shell that protects the brain tissue, and without this shell, the brain tissue is more susceptible to injury. Although the skull is hard, it is actually very susceptible to injury. Bumps and knocks in daily life can easily cause damage to the skull, which may result in situations such as gaps in the skull. Craniocerebral trauma and brain surgery to remove bone flaps, removal of benign tumors or tumor-like tumors from the skull, chronic osteomyelitis of the skull, etc. Due to the change in shape of the defective area of the skull, the scalp is subjected to atmospheric pressure, which causes it to sink in and compress the brain tissue, posing a serious threat to human health. Once the cranium is damaged, cranial bone repair must be performed in a timely manner. Cranial repair is a common neurosurgical procedure for repairing cranial defects caused by traumatic brain injury and craniotomy. The purpose of cranial bone repair for cranial defects is to solve the problems of lack of effective protection of brain tissues in the defective area, obstacle of blood supply, abnormal cerebrospinal fluid circulation, etc., as well as to solve the problem of shape repair and plastic surgery. Cranial bone repair can completely compensate for the above problems, but more importantly, when is the best time to do cranial bone repair? When is the best time for cranial repair? Patients with cranial defects often have a heavy burden of thought such as insecurity, and can cause headaches, dizziness, fear of vibration and other syndromes. The longer the cranial defect, the higher the incidence of cranial defect syndrome and secondary brain damage. In order to restore the airtightness of the cranial cavity, keep the physiological intracranial pressure stable and reduce the cranial defect syndrome. Cranial bone repair should be performed for cranial defects with a diameter of 3 centimeters or more, without muscle coverage, and without contraindications. The timing of cranial bone repair surgery is generally considered appropriate for repair 3 to 6 months after craniotomy and debridement. Cranial defect repair 3-6 months after decompression surgery has the following advantages: (1) to restore the original shape of the cranial cavity as soon as possible, which is conducive to the restoration of normal intracranial pressure and cerebral physiological function. (2) Preventing cerebral tissue displacement from pulling and twisting cerebral blood vessels, causing cerebral tissue ischemia and necrosis, thus reducing the further aggravation of cerebral nerve dysfunction in cerebral blood vessel-supplying areas. (3) Prevent cerebrospinal fluid circulation obstruction caused by brain tissue displacement, which may induce subdural effusion on the opposite side of the defect or longitudinal fissure. (4) Restore the shape of the skull as soon as possible, which can not only relieve or eliminate headache, dizziness, memory loss and other complications caused by the cranial defect, but also relieve the patient’s anxiety or fear in time. Meanwhile, the material of skull repair is the most critical step. Because it is the repair of cranial tissue, the choice of repair material first requires a high degree of biocompatibility, and the need to ensure a certain degree of strength and stiffness, not only to provide strong enough to protect, but also to meet the needs of intraoperative molding, to achieve the appearance of repair and cosmetic surgery to achieve a satisfactory result. Currently, the best material for cranial bone repair is the new polyether ether ketone (PEEK) material. This PEEK material can be three-dimensional molding, precise anastomosis defect area, and PEEK material can be fused with the autogenous bone, adapting to the growth and development of the skull. In addition, this material is comparable to the performance of autogenous skull bone in terms of elasticity, heat conduction, hardness and stability, making it the perfect material for cranial bone repair. The use of polyether ether ketone peek material for cranial bone repair, in the three-dimensional design of the unique material thickness and mesh aperture design as well as the unique intraoperative tissue separation and reset technology, to ensure that the activity of the tissues, and effectively ensure that the overall appearance of the postoperative appearance of the overall aesthetics. Many cases of cranial bone repair have been completed, achieving good results, and have been recognized by patients with cranial bone defects.