The invention discloses an isobutene catalyst prepared from alcohol solution treated methyl bromide and a preparation method and application of the isobutene catalyst. The preparation method comprises the following steps that firstly, zinc oxide or zinc oxide and zirconia are introduced into a silicon dioxide carrier; secondly, the material obtained in the first step is treated through an alcohol water solution; thirdly, the catalyst precursor obtained in the second step is subjected to bromination treatment, the content, by weight, of the zinc oxide in the prepared catalyst is 0.5-20%, and the content, by weight, of zinc bromide is 10-50%. The catalyst can remarkably improve the selectivity of isobutene.