(1) The pharyngeal opening of the eustachian tube is blocked by pressure: such as adenoid hypertrophy, hypertrophic rhinitis, nasopharyngeal tumor or lymphatic tissue hyperplasia, and prolonged nasopharyngeal stuffing, which directly block the pharyngeal opening of the eustachian tube and affect its opening. (2) After radiation treatment of the head and neck: swelling of the mucosa of the nasopharynx and eustachian tube, local venous and lymphatic flow obstruction, resulting in narrowing of the lumen, may also lead to secretory otitis media. (3) The muscles that govern the opening and closing of the eustachian tube in children, such as the palatal sail muscle, are weak, which affects the opening function of the eustachian tube. This is one of the anatomical and physiological bases for the high incidence of pediatric secretory otitis media. (4) Often secondary to upper respiratory tract infection, it can be assumed that the disease may be related to bacterial or viral infection. (5) Metaplasia can cause edema of the mucosa of the eustachian tube, leading to obstruction of the eustachian tube, resulting in negative pressure in the middle ear and causing exudation or hypersecretion. (6) Improper use of antibiotics in acute otitis media, such as insufficient dose, insufficient course of treatment, or resistance of bacteria to drugs, can cause inflammation to persist. In addition, relying solely on antibiotics and neglecting tympanotomy is also a cause of secretory otitis media.