The mouth breathing becomes ugly mostly refers to the gradual partial change of the upper jaw under the effect of airflow impact when open-mouth breathing is performed for a long time, and then the facial bone becomes impaired, resulting in adenoid face. Adenoid face is usually detected and corrected early, but once adenoid face is formed, it is difficult to recover, and it can be improved through clinical treatment. The adenoid face is mainly due to the nasopharyngeal ventilation caused by adenoid hypertrophy and adenoid inflammation. In order not to affect normal breathing, some people will adopt open-mouth breathing, gradually appearing symptoms such as elongated maxilla, protruding upper incisors, thickened lips and uneven teeth, which may be accompanied by nasal congestion, runny nose, nasal sound when speaking, snoring sound when sleeping, and hearing loss may also occur, and in patients with longer time, it will gradually cause ischemia and hypoxia in the head and neurological symptoms, such as mental discomfort, memory loss, and slow reaction. When symptoms appear, it is important to seek medical examination in time to avoid delaying the condition. Adenoidectomy can be performed to improve the symptoms of nasal obstruction and restore breathing through the nose. If the patient is older and the adenoid face has been formed, it is difficult to restore to the normal level and can be treated through surgical plastic surgery under the guidance of a professional doctor, but the post-operative effect also varies from person to person and the patient needs to be psychologically prepared. In addition, since open-mouth breathing mostly starts in children, parents are advised to pay attention to observe children’s sleep at all times, and if symptoms such as persistent snoring, open-mouth breathing and mouth depression occur, they need to seek medical examination and start early intervention.