Effect of nanoparticles (Fe and Fe/Ni) on the biodegradation of phenol by BFN at different pH values (8.0, 6.0 and 3.0) was investigated. The results showed that the degradation of phenol was promoted in the presence of the Fe and Fe/Ni nanopracticles at pH = 8.0 and pH = 6.0, whereas only Fe nanoparticles improved the biodegradation of phenol at pH = 3.0. The former could be ascribed to the H2 generated from iron corrosion, which can contribute to the degradation of phenol by BFN and the growth of BFN by providing electrons, while the latter could be attributed to that the increasing pH value resulted from the generation of OH from iron corrosion was beneficial to the growth of BFN. The improved growth of BFN in the presence of the metallic nanopracticles was observed in medium with various pH values. The results obtained from SEM and EDS demonstrated that the nanoparticles were adhered to the surface of BFN, but there was no significant change in the morphology of the microbes. Overall, nanoparticles (Fe and Fe/Ni) can facilitate the growth of BFN and thus the degradation of phenol.