The influence of the preparation method on the properties of a supported catalyst for the metathesis of ethylene and trans-butene-2 to propylene has been studied. A catalyst composed of molybdenum oxide supported on an alumina-carbon sorbent (manufactured by SKTB Katalizator, Novosibirsk, Russia) has been examined. It has been shown that the addition of nitric acid to an ammonium paramolybdate solution for impregnation during the preparation of the catalyst has an effect on the morphology and phase composition of the active component formed on the support surface, thereby improving the catalytic properties of the resulting systems in the metathesis of ethylene and trans-butene-2 to propylene.