We prepared the cylindrical $gamma-alumina$ pellets of 5 mm in diameter and 10 mm in average length using amorphous alumina and pore generating agent. The pellets were immersed in an aqueous solution of the mixture of $Fe(NO_{3})_{3}{cdot}9H_{2}O$ and $CH_{3}COOH$. They were then hydrothermally treated at $200^{circ}C$ for 3 h in autoclave, dried and calcined. For the application as an environmental catalyst, we investigated the decomposition characteristics of aniline and the initiation characteristics of $OH^{cdot}$ conversion action in $O_{3}$ environment with or without the $Fe_{2}O_{3}$ supported y-alumina catalyst and $O_{3}$ molecule.