The invention discloses an ethylbenzene dehydrogenation catalyst and a preparation method thereof. A carrier of the ethylbenzene dehydrogenation catalyst is a ZSM-5/MCM-48 micro-porous/meso-porous composite molecular sieve; an active component of the catalyst is V2O5; an auxiliary of the catalyst is CeO2. According to the ethylbenzene dehydrogenation catalyst and the preparation method thereof disclosed by the invention, the ZSM-5/MCM-48 micro-porous/meso-porous composite molecular sieve is used as the carrier; the carrier is combined with the pore structural characteristics of two molecular sieves including micro-porous ZSM-5 and meso-porous MCM-48, therefore, high dispersion of the active component and the auxiliary is favorably realized; a rapid diffusion and transfer channel can be provided for molecules; generation of deposit carbon is slowed down; the catalytic performance of a vanadium-based catalyst for preparing vinyl benzene through ethylbenzene dehydrogenation in a CO2 atmosphere is improved; in addition, compared with the prior art, the ethylbenzene dehydrogenation catalyst has the advantages that under same reaction conditions, the catalytic performance is far prior to that of a traditional uni-structure molecular sieve loaded vanadium catalyst.