The invention relates to a catalyst for preparing olefin through dehydrogenation of isobutene and a preparation method of the catalyst, aiming at solving the problems that the existing catalyst for preparing olefin through dehydrogenation of isobutene has low dispersity of active components, low catalytic activity, and low selectivity of target olefin. According to the catalyst for preparing olefin through dehydrogenation of isobutene and the preparation method of the catalyst, SiO2 is used as a carrier, vanadium oxide and platinum group elements with high dispersity are used as active components, oxides of rare earth elements and oxides of alkali metals are used as auxiliary components, the auxiliary components are loaded by an impregnating method, mild CO2 is used as an oxidizing agent to realize reaction for preparing olefin through dehydrogenation of isobutene, and then coke-burning regeneration of the catalyst is carried out. The catalyst can solve the above problem well and can be used for industrial production of light olefin through dehydrogenation of light alkane.