In the current life, there are many kinds of causes of cranial defects, such as traffic accidents, falling objects, debridement decompression, craniosynostosis, etc. Cranial defect not only affects the aesthetics, but also brings insecurity to patients, and even causes cranial defect syndrome, intracranial pressure instability and other related problems, which affects patients’ life and work, so it is necessary to repair the skull as early as possible. The main purposes of cranial repair are: 1) to improve the blood circulation of brain tissue; 2) to improve the cerebrospinal fluid circulation of brain tissue; 3) to release the adhesions at the cranial defect of brain tissue; 4) to keep the stable pressure of brain tissue from changing with the external air pressure; 5) to improve the skull appearance of patients; 6) to relieve or eliminate the cranial defect syndrome of patients (mainly manifested as headache, dizziness, restlessness, apprehension, fear, concentration in concentration, etc.). What kind of repair material is better? The ideal cranial repair material must have the following conditions: ① easy to shape and fix; ② small tissue reaction, non-toxic; ③ chemically stable, not corroded, absorbed, aging in the tissue; ④ can pass X-ray; ⑤ no heat transfer, non-conductive. The main cranial repair materials applied at present are: 1. Titanium mesh The more widely used material in clinical practice is titanium mesh material, but titanium mesh repair cranial rejection is an inevitable problem. Because titanium mesh, a metal material, is more different from human tissue, the histocompatibility is not particularly ideal, so some patients will have rejection reactions. Postoperative problems such as chronic pain, more subcutaneous fluid, sensitivity to hot and cold reactions, and chronic cutting ulcers may occur, and it will also affect postoperative medical examinations such as nuclear magnetic and CT. 2, PEEK material peek material is highly insulated, the patient’s repair will not feel any change in the weather environment; it has excellent mechanical properties, strong impact resistance, and can effectively protect the human brain tissue; from the point of view of cosmetic appearance, peek material is designed according to the patient’s brain CT data, using 3D printing technology to produce a perfect match with the bone window skull; as a non-metallic material, it has stable performance, can be repeatedly autoclaved, and has no risk of surgical infection, thus reducing the occurrence of complications. Therefore, skull repair with peek material is a better choice for many people.