Life after someone suffered a car accident or other traumatic brain injury, intracranial lesions for craniotomy, the patient was cut off the skull for a variety of reasons, and sometimes can not be put back as it is, so the formation of the skull defect, so that the soft tissue of the brain to lose the hard shell of protection, in the face of such a situation, the cranial defect of the patient is more fragile than ordinary people. Cranial defects require cranial repair surgery, mainly due to the change in shape of the cranial defect area and the scalp being subjected to atmospheric pressure, which causes it to sink in and compress the brain tissue. Patients often have a heavier 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, maintain physiological intracranial pressure stability, and alleviate cranial defect syndrome, cranial bone repair should be performed for cranial defects with a diameter of more than 3 centimeters, with no muscular coverage, and without contraindications. The choice of material for cranial bone repair is also very important, which can effectively reduce the rate of infection, rejection reaction and so on. To do cranial bone repair, the current medical profession uses the new PEEK material, PEEK (polyether ether ketone) has high temperature resistance, corrosion resistance, strong, and at the same time, good toughness, does not affect the postoperative review, etc. PEEK material shaping is generally used in the overall 3D printing technology shaping melting and casting, so it can be personalized according to the patient’s cranial bone defects in the part of the situation of the perfect shaping. What is the danger of cranial defects, through the above introduction we understand the danger of cranial defects, seriously affecting the health of patients, so cranial repair is very necessary, it is recommended that patients early to professional cranial repair hospitals, as soon as possible to restore health.