Cranial defect is required for skull repair surgery, mainly because the shape of the skull defect area is changed and the scalp is affected by atmospheric pressure, which makes it invaginate and compress the brain tissue. Patients often have a heavy burden of thoughts such as insecurity and can cause syndromes such as headache, dizziness and fear of vibration. The longer the cranial defect, the higher the incidence of cranial defect syndrome and secondary brain damage. In order to restore the cranial cavity confinement, keep the physiological intracranial pressure stable and reduce the cranial defect syndrome, cranial repair should be performed for cranial defect diameter above 3 cm, without muscle coverage and without contraindications, and the operation time is usually chosen after three months of craniotomy. The choice of materials for cranial repair is also very important to effectively reduce the infection rate and rejection reaction. Currently we use polyether ether ketone PEEK material for cranial repair, PEEK (polyether ether ketone) has many advantages such as high temperature resistance, corrosion resistance, sturdiness, and at the same time good toughness, and does not affect post-operative review, etc. PEEK material is generally shaped using 3D printing technology for overall shaping and fusion casting, so it can be personalized and perfectly shaped according to the patient’s cranial defect site. Furthermore, PEEK significantly reduces the rate of subcutaneous fluid accumulation and subcutaneous infection after surgery. It is recommended that patients with skull defects should go to a regular hospital early to take new polymer materials to repair their skull and regain their health as soon as possible.