In order to remove the NO contained in exhaust gas by the non-selective catalyst reduction method, the catalysts were prepared by varing the loading amount of Ag and V into γ-Al2O3. The conversion of NOx using the prepared catalysts was studied by varying the temperatures, O2 concentrations and SO2 concentrations using. The influence of the catalyst structure on NOx conversion was studied through the analysis of the physical properties of the prepared catalysts. In the case of AgV/γ-Al2O3 catalyst, the NOx conversion was lower than that of Ag/γ-Al2O3 at higher temperatures but higher than that of Ag/γ-Al2O3 at lower temperatures. Even though SO2 was contained in the reaction gas, the NOx conversion did not decrease. Based on the analysis including XRD, XPS, TPR, and UV-Vis DRS before and after the experiments, the experimental results were examined. The results indicated that, NOx conversion decreased at higher temperatures since Ag oxide could not be maintained well due to the addition of V, whereas it increased at temperatures lower than 300 ℃ due to the catalytic action of V.