Keratin (K) is the main component of the epithelial cell mesenchymal cytoskeleton, which protects the integrity of epithelial cells and maintains the function of normal epithelial cells. The expression of keratin affects epidermal proliferation and differentiation, and so as to be used as a marker for proliferation, differentiation and migration of keratinocytes. Middle ear cholesteatoma is one of the common ear diseases. In the middle ear cholesteatoma, keratinocytes over-proliferate and keratin debris accumulates. In this paper, we reviewed the recent studies on middle ear cholesteatoma and explained the possible mechanisms of keratin in the pathogenesis of middle ear cholesteatoma from the aspects of "proliferation" and " bone resorption ". At the same time, the existing problems as well as the prospect of the future research were discussed.