It is difficult to apply microbial fuel cells (MFCs) basing on activated carbon air cathode in practical application because of the low efficiency of oxygen reduction reaction. Thus, exploring high-efficient catalyst to improve the cathode performance is of emergent significance. Herein, we synthesize an activated carbon-supported Fe-Ag-N multi-doped graphene as the air cathode catalyst in MFCs via a simple preparation and calcination of Fe-Ag prussian blue analogues. As proved, the designed catalyst contributes to the decrease of the cathode's diffusion resistance and charge transfer resistance; mean-while it immensely promotes the kinetics towards ORR by accelerating the migration of electron from the encapsulated bimetals to the surrounding carbon structure, indicating that the deposit of multi-doped graphene catalyst reinforces the cathode's conductivity and expedites the electron transfer process. The output power performances indicate that a highest maximum power density reaches up to 1956.45 mWm(-2), which is 7 times higher than that of the control, foreboding the catalyst's potential application in MFCs. (C) 2019 Elsevier Ltd. All rights reserved.