The invention provides a Mo/mordenite-aluminum oxide catalyst for butylene disproportionation and a preparation method and application thereof. The catalyst takes the mixture of mordenite-aluminum oxide as a carrier, and the supported active component is an oxide of molybdenum; the mordenite molecular sieve is evenly mixed with a certain proportion of aluminum oxide and water, then molded by extrusion, dried and roasted to be put in ammonium solution for exchange to be prepared into an H-type mixture carrier; and the mixture carrier is dipped in the solution containing molybdenum element, the load of the metal molybdenum is 2-30 percent, and the mixture carrier is prepared into the Mo/mordenite-aluminum oxide catalyst after being dried and roasted. The provided catalyst is used in reaction of propylene and amylene prepared by 1-butylene disproportionation and can prepare propylene and amylene with high transformation ratio, high selectivity and high stability.