Fe-ZSM-5 and K-Fe-ZSM-5 zeolites were prepared by ion-exchange, followed by hydrothermal treatment at different temperature. After characterization by means of XRD, nitrogen adsorption/desorption, NH3-TPD, 27Al MAS NMR, FT-IR, UV-vis and H2-TPR, the samples have been investigated as catalysts for the one step oxidation of benzene to phenol by N2O as oxidizing agent. The results show that part of Fe2O3 particles are loaded on the surface and the pore of the Fe-ZSM-5 zeolite by ion-exchange. After hydrothermal treatment, Fe-ZSM-5 zeolite occurs framework dealumination and Br豱sted acid sites is decreased; The amounts of Fe2O3 particles decrease and iron-ions can be migrates to form highly active Fe3 sites. These result in that N2O molecules can be adsorbed on these highly active Fe3 sites and decompound to α-O. Before and after hydrothermal treatment, N2O conversion is almost unchanged in one step oxidation of benzene to phenol. Phenol selectivity is gradually increased with increasing temperature of hydrothermal treatment. However, the phenol selectivity is decreased because kalium ion is introduced into Fe-ZSM-5 zeolite.