The invention provides a catalytic additive capable of decreasing the FCC exhaust gas NOx emission amount and a preparation method thereof. The catalytic additive is mainly composed of, by weight, 10-30% of a perovskite component with the general formula being CeAlxZnyCozO3, 15-35% of ternary hydrotalcite, 5-20% of lanthanide oxide except for cerium, 5-20% of transition metal oxide, 3-15% of VA group metal oxide and 5-45% of pseudo-boehmite. The catalytic additive contains no precious metal, the CO combustion-supporting performance is low, the NH3 and HCN removal rate is high, and the catalytic additive is applicable to incomplete regeneration FCC on any working condition, so that the catalytic additive has the advantages of being low in cost, not damaging equipment, being high in removal rate and wide in application range and the like.