The skull is an essential bone in our body. The skull has a supporting and protective role for the brain, it protects the brain from external aggressions and provides us with a safe and stable intracranial operating environment. But things happen and there are always external factors that cause damage to the skull. Some people ask if it is possible not to repair a cranial defect. The answer is predictable, just like building a house with a brick missing in the middle, the building is incomplete and the facilities inside the house are not well protected. Similarly, a skull defect can cause the loss of the barrier protecting the brain and damage some parts of the skull, thus affecting the normal activities of the body. Skull defects that are not repaired in time can cause a variety of symptoms that can endanger our health and also seriously affect our appearance. Some patients have headache, dizziness, and serious fear of bulging and collapse of the defective part, which will cause depression and low self-esteem in the long run; some patients will have poor self-control, concentration and memory loss. Moreover, long-term cranial defects will cause brain tissue atrophy and cystic changes. Skull defects must be repaired, and the materials for repair must be carefully selected. There are many kinds of materials for skull repair in the market, each with its own advantages and disadvantages, and there are many clinical examples of postoperative problems due to unsuccessful selection of repair materials. Although titanium mesh is an improvement over traditional materials, there are still some shortcomings and defects that make it inevitable for patients and families to feel bad about it. Fortunately, through the continuous exploration and efforts of medical experts, polyetheretherketone, commonly known as PEEK, is the perfect solution to the defects of other materials. The repair will not cause any rejection by the patient and will allow the patient to achieve the best possible recovery. Currently, PEEK has been used to repair cranial bones in clinical practice with excellent results.