Obstructive sleep apnea hypoventilation syndrome (OSAHS) is caused by some causes of upper airway collapse during sleep, resulting in upper airway obstruction, causing apnea and hypoventilation, accompanied by snoring, sleep structure disorders, frequent oxygen saturation decreases, daytime drowsiness and a series of syndromes, narrowing and obstruction of any part of the upper airway can cause OSAHS, frequent Apnea can cause hypoxemia and hypercapnia, which can lead to progressive damage of multiple organs and even cardiac arrest. There are three types of sleep apnea hypoventilation syndrome, one is central sleep apnea hypoventilation syndrome’s, the second is obstructive sleep apnea hypoventilation syndrome, or OSAHS, which is caused by collapse of the upper airway, and the third is mixed sleep apnea hypoventilation syndrome, which is apnea hypoventilation syndrome that contains both of these factors. OSAHS can be caused by narrowing and obstruction of any part of the upper airway. The site of obstruction is slightly different in children and adults; in children, the site of obstruction is usually adenoid hypertrophy of the nasopharynx and tonsillar hypertrophy of the oropharynx; in adults, the site of obstruction is nasal factors: nasal septal deviation, sinusitis, nasal polyps, nasal tumors. Pharyngeal lesions such as narrowing of the pharyngeal cavity, tonsillar hypertrophy, reduced muscle tone in the elderly, and inward movement due to relaxation and collapse of the pharyngeal wall lead to respiratory obstruction. Polysomnography monitoring can monitor apnea and hypoventilation index, oxygen saturation, electrocardiogram, electroencephalogram, pulmonary function, etc. We hope to have a proper understanding of sleep snoring in the future.