Abstract: Using composite oxides of the Rare Earth and Cheap metals as catalyst, this paper studied the catalytic oxidation of waste gas containing hydrazine. The influence of hydrazine concentration in waste gas, space velocity, environmental temperature, oxygen concentration on the purification efficiency was discussed. The usefull life of the catalyst was also investigated. When the hydrazine concentration in air is 4000~5 000 mg/L, environmental temperature is 14℃, space velocity is 10000/h, the purification efficiency keeps 100% for more than 100h. The quantity experiment and cold operation investigation both give satisfied results.