The skull plays a very important role in our life. An intact skull helps to maintain the aesthetic appearance, the complete closure of the cranial cavity, the stability of normal intracranial pressure, and the normal operation of cerebrospinal fluid and cerebral blood. Once a defect occurs in one part of the skull, it can cause many problems to the health and normal life of the patient. One of the obvious hazards of cranial defects is the lack of strong protection for the brain tissues, which can easily put them in various dangers and cause secondary injuries, and from this perspective, patients with cranial defects are at greater risk than ordinary people. There is also an incomplete cranial cavity, atmospheric pressure can act on the intracranial tissues, resulting in unstable intracranial pressure and changes in the intracranial environment, then cerebrospinal fluid circulation and cerebral blood circulation may be impaired, which may easily cause a series of cranial defect syndrome. In addition. Cranial defects also have a great impact on the patient’s appearance and psychological aspects. The collapse or bulging of the defective area makes the original asymmetrical head shape even more unattractive, resulting in a strong sense of inferiority, reluctance to participate in social life, emotional depression and loneliness. Especially children, because of their young age, are not willing to reveal themselves to their parents too much, which is very detrimental to their healthy growth, and even more so, the cranial defect may cause the problem of intellectual decline. Cranial defects should not be taken care of, and timely repair is the first priority. Many parents under the age of 10 often ask how old can children be for cranial repair and can cranial repair be done at the age of three? Most neurosurgeons have now reached a consensus that a defect of 3 cm or more can be repaired at the earliest opportunity, with very few depending on the circumstances. The time for cranial repair in children is 3 years of age or older, so cranial repair is possible at the age of three.