Secretory otitis media is old and recurrent with persistent etiologic or predisposing factors. At present, it is believed that Eustachian tube dysfunction, mechanical obstruction, localized infection of the middle ear and metamorphosis are the main etiological factors. 1. Dysfunction: the muscles that drive the opening and closing of the Eustachian tube are weak in contraction, the cartilage of the Eustachian tube has poor elasticity, and the wall of the cartilaginous section of the Eustachian tube is prone to collapse, leading to dysfunction. Children’s Eustachian tube is short and wide, nearly horizontal, easy to make the nose and pharynx infection spread to the middle ear, which is one of the anatomical and physiological basis of the high incidence of secretory otitis media in children. 2. Mechanical obstruction: such as adenoid hypertrophy, hypertrophic rhinitis, nasopharyngeal tumors or lymphatic hyperplasia, long-term filling of the posterior nostril and nasopharynx. 3. Localized infection of the middle ear: bacteriological and histological findings as well as clinical signs suggest that secretory otitis media may be a mild or low-toxicity bacterial infection of the middle ear. Bacterial endotoxins may play a role in the pathogenesis, especially in the chronicity of the disease. 4. Metaplasia: Children’s immune systems are not fully developed, which may also contribute to recurrent episodes of secretory otitis media in children. The presence of antibodies and immune complexes specific for inflammatory mediators and bacteria in the middle ear effusion, as well as the presence of the complement system and lysosomal enzymes, suggests that chronic secretory otitis media may be part of a pathologic process mediated by anti-infective immunity. There are also other causes of recurrent secretory otitis media, and patients are advised to actively consult a doctor for systematic examination and clear diagnosis.