Use of iron phthalocyanine (FePc) filtration membrane cathode in microbial fuel cell (MFC) is a promising method to simultaneously improve electrocatalytic activity and antifouling performance. The filtration membrane cathode with the optimal content of 0.07 g FePc (FePc-7) exhibited the best oxygen reduction reaction (ORR) activity with the highest current density (12.0 A m⁻²) and the lowest charge transfer impedance (4.1 ± 0.4 Ω), which was 99% higher and 69% lower than the control (12.0 A m⁻² and 4.1 ± 0.4 Ω). Besides, the FePc-7 had the largest transferred electrons (n = 3.97), indicating that the ORR occurred through a direct 4e⁻ transfer pathway. The foregoing could be attributed to the Fe-N_x structure of FePc to form more energetically catalytic active sites, which could greatly increase the onset potential and reduce the adsorption energy of O₂. The addition of FePc has remarkably increased the COD removal ratio and the FePc-7 showed the minimum effluent COD concentration of 21.7 ± 1.2 mg L⁻¹, which was decreased by 61% compared to the control. Moreover, the antifouling performance was also a key factor maintaining excellent electrocatalytic activity and the FePc-7+E (E was electric field) obtained the lowest flux attenuation ratio of 12.9 ± 0.3% with the thinnest fouling thickness of 55–60 μm, which was decreased by 47% than the control+E. The FePc filtration membrane cathode exhibited outstanding antifouling performance due to its superior hydrophilicity and stronger electrostatic repulsion force under electric field. This work provided an easy and facile modification method for the development of high-performance filtration membrane cathode in the MFC.