It is harmful for children to pull out four teeth during orthodontics, but the advantages outweigh the disadvantages. There will be pain during tooth extraction, bleeding after tooth extraction, and infection due to improper nursing. Children need to choose a suitable plan according to the specific situation to correct their teeth. Some children have crowded teeth, which not only affects the appearance, but also affects the basic chewing function. It is necessary to extract the teeth with small volume and small function in order to successfully complete the orthodontic function.