The orthodontic treatment during the period of milk teeth includes early preventive orthodontic treatment and early interceptive orthodontic treatment, which is suitable for those who have abnormal milk teeth or newly erupted permanent teeth or have bad habits in the oral cavity. 1. Early preventive orthodontic treatment. It is applicable to the early loss of milk teeth or first molar, and the use of orthodontic appliances to maintain the length of the dental arch to restore a certain chewing function. If the milk teeth need to be extracted for treatment of milk teeth, consider traction eruption treatment according to the situation, and if the permanent teeth erupt abnormally, an eruption stopper can be used to prevent the teeth from erupting prematurely. 2. Early interceptive orthodontic treatment. Early interceptive orthodontic treatment is suitable for children with bad oral habits, abnormal sucking, swallowing, spitting, or mouth breathing habits, which will lead to dental arch deformity, and can be corrected with movable orthodontic appliances. With the occurrence of malocclusion of milk teeth, it is recommended to go to a professional dental hospital for timely correction.