A study of a catalyst for NOx reduction used for a diesel engine of cars is done frequently currently. In the recent studies, Ag/Al2O3 catalyst system is considered to be a candidate for practical use. The ceramics molding body (ceramics honeycomb etc.) is used as a border brim of these catalysts usually. However, there is a problem. Strength to thermal shock is low. Moreover, it is not easy to go up in the center part until the catalyst operating temperature because thermal conductivity is bad and is obstructed working of the catalyst to the first stage of the reaction for that. In this research, the Ag/Al2O3 catalyst system was coated to stainless steel (SUS304) substrate that forming it is easy and heat conduction rate is good. The aluminum nitrate was used as a binder. After the binder is dissolved in the ion exchange water, the stainless steel substrate coated Ag/Al2O3 catalyst is sintered. In order to optimize coating conditions, the heating temperature, the sintering time, the density of the binder and the amount of the coating powder addition as well as the dip coating frequency were changed, respectively.