The process of orthodontic treatment for nine-year-old children is as follows: 1, oral examination, taking full-mouth surface tomography and cephalometric films, preparing observation models, and formulating orthodontic treatment plans after comprehensive analysis. 2, extraction of buried multiple teeth and malocclusions in the alveolar bone, and removal of retained milk teeth and loose remnants of roots and crowns present in the dental row. 3, as nine-year-old children are in the period of permanent tooth replacement, they can wear movable orthodontic appliances, and bonding brackets on the incisors. 4. To prevent loosening of the roots of the baby teeth, the aligner abutment can be used as a strong support to suspend a rubber band between the orthodontic arch wire and the brackets, with elastic traction to move the incisors slowly and control the direction of the incisors. 5. After the incisors have moved to their normal position, the brackets can be worn out and the aligners removed.