Cranial depression is mostly caused by craniocerebral injury, and a small portion is caused by congenital causes. The medical definition of depressed skull caused by craniocerebral injury is that the skull bone is detached from its original part due to traumatic injury, and depressed to a certain degree internally, which is called depressed fracture, also called skull depression. There are certain principles for the treatment of depressed skull fracture, for infants and young children’s depressed skull, if the degree of depression is not more than 5mm, no clinical symptoms do not need to be dealt with, in the process of pediatric development can be reset or repaired on their own. In adults, if the skull depression is more than 10mm, and there is functional symptom of the adjacent brain tissue, surgical repositioning is needed. There are also medical reasons, such as if the skull plate is sunken inward due to fixation problems when the skull is restored during cranio-cerebral surgery, it needs to be treated and fixed again surgically.