A novel anode modified by 1,5-dihydroxyanthraquinone/multiwalled carbon nanotubes (DAQ/MWCNTs) composite was fabricated in order to improve its electrochemical performance in marine sediment microbial fuel cell (MSMFC). The number of microbes on the DAQ/MWCNTs modified anode is 18.02 times of blank anode, and it has the best electrochemical performance compared with other anodes. Its exchange current density and biofilm capacitance are 1472.15 times and 18.66 times higher than that of blank anode, respectively. The maximum power density of composite modified MSMFC (890.12 mW.m(-2)) is 3.01-fold of blank cell (296.11 mW.m(-2)). The mechanism analysis of DAQ/MWCNTs shows that DAQ, as an electron-transfer mediator, can accelerate electron transfer to benefit the electrochemical performance of anode. This provides a new anode modification method for the development of high power MSMFC as long-term power source to drive monitoring instruments.