Cholesteatoma otitis media is a common otologic condition, mostly secondary to acquired cholesteatoma, which occurs in children and adolescents as a result of chronic suppurative otitis media with local stimulation of epithelial hyperplasia. Secondary cholesteatoma originates from the epithelium of the external auditory canal, which enters the tympanic chamber from the perforation of the relaxed or tense part of the tympanic membrane and grows along the bone towards the superior tympanic chamber and sinus. The epithelium and keratinized material cannot clean themselves and accumulate into a mass, which gradually increases in size and forms a cystic cholesteatoma lesion. The inner wall of the cyst is lined with compound epithelial cells, and the cyst is filled with exfoliated epithelium, keratinized material and cholesterol crystals, and inflammatory exudate and granulation tissue can be seen around it. The causes of bone destruction caused by cholesteatoma are 1) the compressive resorption of surrounding bone caused by the growth of cholesteatoma; 2) the epithelium at the base of cholesteatoma and the granulation tissue under it secrete collagenase, and this collagenase and other protein hydrolases can break down the collagen fibers in the bone and cause bone erosion and resorption. Before the application of CT, the diagnosis of cholesteatoma otitis media mainly relied on medical history and ear examination, and the traditional auxiliary examination method was mammography or multi-track body layer photography. However, due to its low resolution, it was very easy to miss or misdiagnose the disease. With the widespread use of CT, especially high-resolution CT, it has shown incomparable advantages in the diagnosis of ear diseases and can make precise judgments on the fine anatomy of the temporal bone and the extent and degree of lesion invasion.