The facial changes caused by sleep mouth breathing are usually set at the age of 8 years old, and thereafter, no matter how to correct them, they will have less impact on the child’s face shape. Children’s mouth breathing habits are mostly caused by adenoid hypertrophy. After long-term sleep mouth breathing, children will have a long maxilla, high arched palate, uneven teeth, and short chin adenoid face, which has a great impact on the “face”. Adenoids generally start to develop when children are 3-5 years old, proliferate the most around 8 years old, and shrink after 10 years old. If adenoid hypertrophy is not severe, early breathing through the nose can be practiced. If adenoid hypertrophy is too severe, it needs to be removed to prevent the adenoid face from intensifying. However, if this period is not intervened, after the age of 8 years the child’s facial shape is basically set and cannot be treated by adjusting breathing. Parents may consider orthodontic treatment to restore the child’s teeth to their proper alignment and increase the aesthetics of the face.