According to the growth and development process and general characteristics of children, they can be divided into the following age groups: (1) Infancy: from birth to 1 year old; (2) Early childhood: 1-3 years old, also known as nursery age; (3) Preschool: 3-6 years old, also known as kindergarten age; (4) Adolescents: 12-19 years old. Oral health care focus is different in different periods. In the infant period, the main emphasis is on breast milk diet guidance, and the milk teeth start to erupt around six months, for the possible problems when teething, use the corresponding preventive measures, pay attention to oral hygiene, assist in cleaning the erupted teeth at night before going to bed, especially formula-fed infants, to prevent the emergence of bottle caries. To benefit the erupted and unerupted teeth. As children grow up, they should pay more attention to the health care of the erupted milk teeth, pay special attention to the prevention of caries, do a good job of oral cleaning and dietary guidance; reduce the intake of sugar, from auxiliary brushing to teaching themselves to brush their teeth, and develop good oral hygiene habits. After the milk teeth are all grown, we should still pay attention to the prevention of caries. For children who cannot brush their teeth carefully, parents should supervise the process of brushing, check the effect of brushing, and maintain the integrity of the milk teeth. When the permanent teeth start to erupt in the preschool and late school years, the caries rate of the milk teeth increases, at this time, we should conduct regular oral examination for children, take caries prevention measures such as C-groove closure, and treat caries early if there is caries.