The characteristics of infant caries: 1.The children’s age of onset is small, the number of involved teeth is large, the scope of caries is wide, the lesion is serious, the progress is fast, the early involvement of pulp and periapical tissue; 2.The uncontrolled caries eventually leads to the milk teeth become the residual crown and root, even the infection of apical tissue, which affects the development of permanent tooth embryo and the chewing function of children; 3.Serious caries leads to eating pain, affects the children’s intake of nutrients. It can lead to low weight and retarded development; 4.The open cavity and residual root can form chronic lesion and cause fever, maxillofacial infection, bacterial endocarditis, rheumatism, chronic nephritis and other systemic diseases; 5.Children’s sleep will be affected by toothache, and research shows that sleep disorder can affect the production of glucocorticoid hormone and interrupt children’s growth; 6.The decayed and missing front teeth can also affect children’s pronunciation, social interaction and normal psychological development. Social interaction and normal psychological development.