Abstract: In microbial fuel cells (MFC), redox mediator can promote the transfer of electrons from microbes to the surface of electrode and enhance converting efficiency of energies. Proteus vulgaris to the performance of MFC is superior to E.coli without the mediator. The combinations of microbes and mediators were studied, and the results shown that the polarization curve of microbial fuel cell with combination of proteus vulgaris and thionine was smooth and stable, the maximal output power reached 128.8mW/m2. Otherwise, the interior resistance of MFC decreased from 1724Ω to 200Ω within thionine, the percentage is 88.4%. The performances of MFCs with the combination of thionine and ferric chelates as co-mediators was better than that with single mediator, and the output power reached 169.3mW/m2 under the conditions of 0.25mmol/L ferric chelates and 0.5mmol/L thionine.