Which is the best time to do a repair for a skull defect? Cranial repair surgery should be done at the earliest possible time when a patient has a cranial injury. Brain diseases must be diagnosed and treated without delay. Which is the best time to do repair for cranial defects? In life, people have cranial defects because of serious head fractures and trauma, due to the lack of protection of the skull, the dura mater is in direct contact with the skin, resulting in localized collapse or protrusion, easy to squeeze, collision and other craniocerebral injuries, causing inconvenience to the patient’s work, life and other inconveniences. Therefore, when the patient has a cranial injury, the cranial bone repair surgery should be done as early as possible. There are two main purposes of cranial bone repair surgery for cranial bone defects, one is for safety and the other is for beauty. The choice of repair material for cranial bone repair surgery is also crucial. If the patient chooses a repair material that is not ideal, it may produce rejection or postoperative infection, leading to the removal of the patient’s repair material and failure of the surgery. Cranial defects do cranial repair surgery better time, for the wound is relatively clean open skull comminuted fracture, no cranial hypertension patients, it is recommended that a phase of cranial repair surgery. For patients with severe closed craniocerebral trauma, giant skull defects caused by cranial hypertension due to decompression of the large bone flap should be repaired about three months after the defect. At present, a few regular hospitals have chosen the new PEEK material as the cranial bone repair material, PEEK material to do cranial bone repair is better than the traditional repair material, and the preoperative is based on the shape of the patient’s cranial defect through the 3D printing, the appearance of the appearance and the previous no difference. Cranial bone repair using PEEK as a repair material, through clinical practice found that PEEK material low density, insensitive to temperature, have high tissue stability, so that it can be sterilized at high temperatures or radiation does not produce deformation. And through a large number of clinical feedback found that PEEK material has ray transmissibility, CT and MRI results will not have an impact.