Abstract: Objective：To investigate the pathology diagnosis and differential diagnosis of the oarian maturity cystic teratoma with squamous cell carcinoma. Methods：To analyse the clinical data，iconography and pathology features of one oarian maturity cystic teratoma with squamous cell carcinoma，and to carry on literature review. Results：Gross appearance：gray beige cystic neoplasm，18 cm × 11 cm × 7 cm，cyst wall smooth containing lipid and hair，can be stripped，without the liquid and mucus composition. There is 4 cm × 3 cm gray solid area with the gray fragile texture of cross section. Microscopically appearance：tumor wall lines squamous epithelium，with the sebaceous glands and hair follicles inside the wall；Visible scattered cells with big hyperchromatic nuclears，showed diffuse arrangement，faint nucleoli，some cells with a spindle type，another little differentiated squamous cell carcinoma area can be visible，which shows the cornification in cell and cell bridges and horny pearl. Immunohistochemical stains results，CK5/6 and PCK：the malignant cells express positively；The pathological diagnosis：ovarian maturity cystic teratoma with area of squamous cell carcinoma in middle-low differentiation. Conclusion：Ovarian maturity cystic teratoma with squamous cell carcinoma is a rare highly malignant tumor，the patients age and postmenopausal age，tumor size，standard pathology examination and distinctive immunohistochemical mark are helpfull to the pathological diagnosis and differential diagnosis.