Cranial repair is a routine procedure in neurosurgery and is a common procedure used to repair skull defects caused by traumatic brain injury and craniotomy. In fact, it is a relatively ancient surgery, which was practiced by our forefathers thousands of years ago. In the thousands of years of development, cranial repair surgery has come a long way and is now quite sophisticated; and the repair materials used in the surgery have undergone constant innovation and upgrading to meet the physiological standards of the human skull. In the early days, a piece of fleece was used to cover the bone window for simple and rough skull repair, and later on, animal bone, metal, plexiglass, bone cement, etc. were gradually used, but they were no longer used for one reason or another. Titanium alloy material was once widely used clinically for cranial repair, so what metal does titanium alloy cranial bone belong to? This titanium alloy is an alloy based on titanium metal with the addition of other elements. Although this titanium alloy material has made some progress compared with the traditional material used before, the overall effect is still not very satisfactory and there are many problems. For example, post-operative infection, post-operative rejection reaction, titanium mesh exposure, such as poor shaping effect, such as the production of cutting pain, etc.. Nowadays, if we use the latest polyetheretherketone material for skull repair, we can receive very good results. Polyetheretherketone, in English, is poly-ether-ether-ketone, or PEEK material for short. It is a special polymer material with excellent physical and chemical properties, and is biocompatible, non-exclusive, and can be shaped in three dimensions to precisely restore the anatomical structure of the skull.