Currently in life, after someone undergoes a craniotomy due to a car accident or other traumatic brain injury or intracranial lesion, the skull cut off by the patient is sometimes not put back as it is for various reasons, so a cranial defect is formed, causing the soft tissue of the brain to lose its hard protective shell, and in the face of this, patients with cranial defects are more vulnerable than normal people. Cranial defect is required for cranial repair surgery, mainly because the shape of the cranial 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 defects with a diameter of 3 cm or more, without muscle coverage and without contraindications, and the operation time is usually chosen between three months and six months after craniotomy. The choice of material for cranial repair is also very important to effectively reduce the infection rate and rejection reactions. The new PEEK material is used as the implant material for cranial repair, and PEEK (polyether ether ketone) has many advantages such as high temperature resistance, corrosion resistance, sturdiness, and good toughness without affecting postoperative review.