Microbial fuel cell (MFC) as a promising technology, which can be used to remove pollutant and generate bioelectricity simultaneously. In this study, the carbon cloth modified with alpha-Fe2O3/polyaniline nanocomposites is used as cathode in a dual chamber MFC for the generation of bioelectricity and electrochemical reduction of hexavalent chromium (Cr(VI)). The carbon cloth decorated with nanocomposites is prepared by a facile electrochemical polymerization technique. The MFC exhibits a complete Cr(VI) reduction at 50 mg center dot L-1 within 36 h, acquiring the obviously high Cr(VI) reduction rate of 1.39 g center dot m(-3)center dot h(-1), and the reduction rate is 1.67 times as high as that of the MFC-Blank (0.83 g center dot m(-3)center dot h(-1)). The MFC with alpha-Fe2O3/polyaniline nanocomposites cathode improves the Cr(VI) reduction rate and output power in MFC. And the maximum power density of this MFC is 1502.78 mW center dot m(-2), which is 1.753 times as high as that of the blank cathode. The improvement is due to the strong conductivity, high mobility of charge carriers and excellent electrochemical performance of nanocomposites. Besides, the power density of MFC modified with alpha-Fe2O3/polyaniline cathode has merely a slight decrease (2.23%) during fifty cycle operation due to the formation of protection layer. Consequently, the carbon cloth attached with alpha-Fe2O3/polyaniline nanocomposites with excellent electrochemical performance can be used as a promising cathode for Cr(VI) reduction and bioelectricity generation simultaneously.