The CO-containing crude hydrogen separated from cold box system is purified in the methanation reactor of the 220 kt/a ethylene plant of PetroChina Dushanzi Petrochemical Company by nickel-based catalysts at 288～323℃ to remove the CO in crude hydrogen. The hydrogen from the reactor is cooled, dried and dehydrated before being sent to downstream users. This paper introduces the use of high temperature catalyst in the methanation reactor of this ethylene plant, compares and analyzes the performance of high temperature catalyst with that of low temperature catalyst, and lists the advantages and disadvantages of these two catalysts. The comparison of the impact of these two catalysts on energy consumption shows that low temperature catalyst has better energy-saving effect.