Ni/CeO2/CaO-MgO catalyst was prepared to catalyze the conversion of cyano-containing exhaust gases into clean fuel gases. Almost all of the large molecular weight cyano-containing compounds were converted into fuel gases with 91.5% reduction of HCN being observed at 650 °C. The introduction of water-steam into the reaction system could further increase the conversion of HCN as well as the production of H2. During the 16 h stability test, the conversion of model compound benzonitrile could be kept around 100% with little carbon deposited. The prepared catalysts were characterized by XRD, H2-TPR, XPS, SEM–EDS and TGA. The effect of CaO and CeO2 modification was investigated. CaO improves the catalyst reducibility and basic properties which are beneficial to the reactants adsorption. CeO2 addition strengthens the oxygen mobility and improves nickel dispersion over the catalyst. The excellent catalytic efficiency and stability could be attributed to the synergy effects of CaO and CeO2 in the catalyst.