Cholesteatoma is the most serious type of chronic suppurative otitis media. Cholesteatoma is not really a tumor as it is usually called, but rather a cystic structure located in the middle ear and mastoid cavity. The inner wall of the capsule is compound squamous epithelium, and the capsule is filled with exfoliated epithelium, keratinized material and cholesterol crystals, while the outer side of the capsule is closely connected to its adjacent bone wall or tissue by a layer of fibrous tissue of varying thickness. Because of the cholesterol crystals in the sac, it is called a cholesteatoma. The characteristics of cholesteatoma otitis media are as follows: chronic and persistent pus flow from the ear, a peculiar foul odor, and a marginal perforation of the tympanic membrane above the relaxed or tense part of the tympanic membrane, with a grayish-white scaly or pea-like substance in the tympanic chamber visible from the perforation. CT examination can determine the extent of the lesion and guide surgery. As the middle ear is surrounded by important organs, such as the brain, cerebellum, large blood vessels, facial nerve and auditory nerve, and the middle ear is separated from the cranial cavity by only a thin bone plate, serious intracranial and extracranial complications may occur as the cholesteatoma grows larger and the surrounding bone is absorbed, such as vaginitis, peripheral facial palsy, dural abscess, sigmoid sinus thrombophlebitis, septic meningitis and brain abscess, etc.; if left untreated, the development may be life-threatening. Patients suffering from cholesteatoma otitis media, regardless of the size of the cholesteatoma, are equivalent to having a time bomb buried in their body, which will explode sooner or later, so cholesteatoma otitis media must be treated with surgery as early as possible; the earlier the surgery, the less likely complications will occur, the greater the possibility of hearing reconstruction to improve hearing, and the better the results of the surgery.