Using chemical vapor deposition methods to prepare carbon nanotubes growing in situ on a carbon felt, graphene and polyaniline were applied to the carbon felt for modifying carbon nanotubes. Microbial fuel cell was constructed with graphene/polyaniline-modified carbon nanotubes as anode, graphite as cathode, and glucose solution as substrate. The effects of electrodes, substrate concentration, and temperature on the properties of microbial fuel cell have been studied. At 38 A degrees C using glucose solution of 1450 mg L-1 and external resistance of 2500 Omega, the optimum output voltage of 687 mV and removal rate of 83% for chemical oxygen demand were obtained in the microbial fuel cell. The prepared nanomaterials are stable and reusable.