The invention relates to a catalyst for a reaction for producing diethylenetriamine by means of hydrogenation of ethylenediamine, and a preparation method of the catalyst, aiming at solving the problems that the existing catalyst is low in activity and selectivity. The catalyst takes alumina as a carrier, and contains 0.1-3wt% of one or two or more of rare earth elements, 5-30wt% of one or two ormore of nickel, copper, iron, cobalt, zinc or tin, and 0.1-5wt% of palladium based on the total weight of the catalyst. The catalyst is prepared by firstly coating the carrier with the palladium element and the rare earth elements, and then coating the carrier with the other elements. The catalyst provided by the invention is used for catalyzing the reaction for producing the diethylenetriamine bymeans of the hydrogenation of the ethylenediamine, can obviously improve reaction activity and product selectivity, and has a very high industrial application value.