The human skeletal system is very large, each bone has its own role, such as the skull, it is playing a very important role, it is like a layer of the brain’s shield, protecting the intracranial tissues from external aggression, to maintain a normal and stable intracranial environment. However, the skull can also be injured accidentally, such as sudden traffic accidents, falling objects and mechanical injuries, etc. These are common causes of skull defects. The seriousness of cranial defects should not be underestimated, it not only affects the aesthetic appearance, but also causes greater harm to the health of the organism, if the collision occurs again, accidentally injuring the intracranial soft tissues, it will be life-threatening. For the problem of cranial defects, clinically it is recommended to do cranial bone repair surgery, that cranial bone repair surgery when to do the most appropriate? This is a case-by-case basis, if the patient’s wound cleanliness is good and there is no intracranial hypertension can be a phase of cranioplasty, but if because of severe closed craniocerebral trauma to do to the large bone flap decompression surgery caused by the skull defect, it is generally recommended that about 3-6 months after the operation and then do the cranial bone repair surgery. Of course, in addition to the timing of cranial repair surgery, the choice of repair material is also very important, good repair material can improve the success rate of the operation, but also reduce the pain of the patient.