Objective:To study the expression of TNF-α in the cholesteatoma and elucidate the role of TNF-α in the destruction of bone.Method:All samples (5 μm paraffin sections) from 25 cholesteatoma cases and 10 normal cases were examined by immunohistochemical SABC method and analysed by computer image.Result:In 25 cholesteatoma cases,TNF-α expressed in the cytoplasm of the full epithelial tissue cells,subcutaneous inflammatory cells and fibroblast.In contrast,the normal cases,there were 6 cases week positive,4 cases negative.The results of the computer image quantitative analysis system showed that the mean optical density of TNF-α was 0.1326±0.0022 in the cholesteatoma epithelial tissue and 0.0868±0.0014 in normal skin epithelial tissue respectively,both of which had significantly differentiation (P＜0.05).Conclusion:TNF-α may be a factor of the destruction of bone of cholesteatoma.