Abstract: The catalysts used for catalytic oxidation HCN were prepared by the impregnation method. To optimize the catalyst, Ce³⁺(Ce(NO₃)₃), Fe³⁺( Fe(NO₃)₃), Cu²⁺( Cu(NO₃)₂) and La²⁺(La(NO₃)₂), were used as active components, while molecular sieves including Hβ, HY, 5A and ZSM5 were used as the carrier. The reaction device was a tubular reactor with constant temperature, and effects of space velocity, reaction temperature and O₂ concentration during the HCN catalytic oxidation process were investigated. The formation rate of NO_x was calculated under 250 ℃. The results suggested that Hβ zeolite impregnated with 0.1 mol/L Cu(NO₃)₂ solution and calcinated at 300 ℃ performed well in HCN removal experiments. When the space velocity was under 6000 h^-1, the conversion rate of HCN was over 95% above 100 ℃, and the conversion rate reached 100% above 200 ℃. The conversion rate of HCN was higher than 95% when φ(O₂) ranged from 1%-5%. The formation rates of NO_x were less than 5% when the reaction temperature was under 200 ℃ and φ(O₂) was below 3%. The HCN removal method discussed in the present study showed its advantages such as high conversion under 200 ℃, less effect of O₂, low NO_x formation rate less than 5%, energy saving and little secondary pollution.