The skull is a very important group of bone tissues in the human body, it is the strong fortress of the brain, the commander of the human body, and it is an important guarantee for the normal operation of the whole human body. Therefore, once a cranial defect occurs, then the human body will be in danger. After skull defect occurs, skull repair surgery should be performed in time. There are many people choose titanium mesh as the skull repair material, the biocompatibility of this titanium mesh material with human body is not particularly ideal, there is a certain rate of rejection. In fact, after years of research and creation by medical experts, there is now a highly histocompatible cranial repair material called polyether ether ketone, or PEEK, which has a near-zero rejection rate for cranial repair. This PEEK material is not only highly histocompatible, this PEEK material can be 3D shaped and 3D printed according to the patient’s skull data, completely restoring the physiological structure of the skull, and after the repair is almost the same as before the defect, in addition, this material has excellent performance in strength, elasticity, individuality, radiopacity, anti-infection, etc., and has become the ideal repair material for patients with skull defects. For the question of whether titanium mesh cranial repair will be rejection, it is still mainly related to the histocompatibility of cranial repair material with human body. In clinical practice, we can often encounter cases of rejection of titanium mesh material after skull repair, and some people have their scalp tissues destroyed due to titanium mesh rejection, resulting in exposed titanium mesh, which is quite scary. After rejection, it is usually necessary to remove the titanium mesh material again and repair it after the scalp tissue grows back. It is recommended that the titanium mesh material not be used again for the repair.