It is normal for a child’s fontanelle to close between the ages of one and one and a half years. Closing before the age of one is medically known as premature closure of fontanelle, which can easily lead to small cranial malformations, limited brain development, and lack of brain volume, and can cause intellectual and motor disabilities. If the fontanelle does not close after two years of age, it is called delayed fontanelle closure, and its common and serious cause is hydrocephalus. In addition, the early and late closure of fontanelle is also related to the following factors: First, it is a genetic factor, especially the closing time of fontanelle of the parents in the family is related. Secondly, it is the baby’s micronutrient status, especially calcium and phosphorus, which are one of the main substances for the mineralization of the skull, and the lack of which may cause delayed closure. Third, is the baby’s nutritional status, brain development, cranial mineralization are related to the balance of nutrients, all kinds of malnutrition will lead to delayed closure.