Low power limits the application of microbial fuel cells (MFCs). Our research mainly focuses on the modification of the electrode and looking for new anode material for high-power marine benthic microbial fuel cells(BMFCs). A MnO2/PPy composite-modified anode was fabricated by in situ chemical polymerization. Surface topography and properties were characterized by scanning electron microscopy and infrared spectroscopy, respectively, indicating that the MnO2/PPy composite is of a mosaic-like' microstructure. The electrochemical performance and wettability of different kinds of anode were investigated respectively. Cyclic voltammetry and linear sweep voltammetry tests show that MnO2/PPy composite-modified electrode has a typical capacitance feature; its capacitance is 3.1 times higher than that of unmodified electrode. Contact angle of the composite-modified anode reduces to 46 +/- 0.5 degrees, and its kinetic activity increased for more than 1.1 times. The maximum output power density of MnO2/PPy composite-modified cell reached 562.7 +/- 10mWm(-2), which is 2.1-fold of the unmodified one. Finally, the composite-modified anode provides an alternative potential choice for high-performance cell, and the possible influence mechanism of composite materials on the BMFCs was also analyzed. Copyright (C) 2016 John Wiley & Sons, Ltd.