Abstract： Objective To explore the biological features of basaloid squamous cell carcinoma (BSC) of the esophagus.Methods Cytokeratins (CK4, CK18 and CK19), epithelial membrane antigen (EMA), carcino embryoantigen (CEA), α-smooth muscle antigen (α-SMA), S-100, laminin (LN), collagen Ⅳ (Col-Ⅳ), neuralspecific enolase (NSE), proliferating cell nuclear antigen (PCNA) and p53 antibodies were used to detect the corresponding antigen expression in 8 cases of BSC with ABC immunohistochemical methods.Results Two kinds of BSC cell components have different responses to the above antibodies. For basaloid cells (BCs), 7 cases were positive for CK19, and were negative for the other 4 epithelial antibodies CK4, CK18, CEA and EMA. BCs of 4 cases were positive to the muscular antibodies α-SMA and S-100, and the hyaline degeneration in the tumor nests was positive for LN and Col-Ⅳ. BCs had a high index of PCNA, with an average level of 54%. For squamous cells (SCs), 7 cases were positive for the epithelial antigen CK4, CEA and EMA, but were negative for CK19, α-SMA and S-100. The index of PCNA of SC was low, with an average level of 25%.Conclusion BSC of the esophagus is a high-malignancy tumor which is of multi-oriented differentiation.BCs represent basal cells which have the tendency of myoepithelial differentiation and have strong proliferation ability, whereas SCs represent typical squamous cell differentiation.