Abstract: Graphite carbon felt anodes were treated with ammonia gas at 500 ℃, 650 ℃ and 800 ℃ respectively to construct marine sediment microbial fuel cells (MSMFCs) . The results show that the microbial and electrochemical activities of the modified anodes are improved evidently. The number (10.420×10¹¹ cfu/m²) of microorganisms attached to the anode modified at 500 ℃ is 2.9 times of that of the blank group, indicating that the ammonia modification at 500 ℃ is beneficial to the adhesion of microorganisms. The cyclic voltammetric capacitance performance of the anode modified at 500 ℃ reaches 62.1 F/m², which is 2.0 times of that of the blank group, showing that this treatment method can increase the redox electrochemical activity significantly. This treatment decreases the anode charge transfer resistance to 1/4 (from 62.39 Ω to 14.46 Ω) and increases exchange current density by 1.1 times of those of the blank group, indicating that the electron transfer kinetic activity and anti-polarization ability are enormously enhanced when the anode is treated at 500 ℃. The output power (60.07 mW/m²) of the anode modified at 500 ℃ is 2.1 times of that (29.17 mW/m²) of the blank group, the long-term output voltage reaches 692 mV and the power generation becomes more stable.