The orthodontic methods for three-year-old children who have developed a diastema are as follows: 1. When the anterior molars are formed, a jaw cushion orthodontic appliance can be worn to cushion the posterior teeth, open the gap, use the hyperbolic lingual reed to push the upper anterior teeth to move labially, and continue to apply force until the anterior teeth are lifted. 2. When the anterior molars are formed, a spiral arch expander needs to be worn to open the midpalatal gap while pushing the maxillary molars to move buccally. 3. If the upper alveolar bone is obviously underdeveloped, anterior traction is needed to stimulate the full development of the alveolar bone. If the lower jaw is over-extended, it is necessary to wear a chin pocket, etc., and to break bad habits such as spitting out the tongue.