Hierarchical ZSM-5 zeolites with nanoflower structure were synthesized by a facile hydrothermal method. From the characterization results, it is proved that the contribution of mesopores to the BET surface area and total pore volume is significant. Owing to the diffusion intensification, the iron loading is greatly increased and the catalytic performance is much better than that of commercial ones, especially for the synthesized samples with high Si/Al ratio. In this work, for Fe/ZSM-5-C sample, it attains 20% N2O conversion at 510°C, which is lower by >70°C compared to the commercial one with close Si/Al ratio. Therefore, Fe-modified mesoporous ZSM-5 zeolites with nanoflower structure show potential in the industrial application.