The invention discloses a rubber asphalt high temperature viscosity reducer, a preparation method and an application thereof. The rubber asphalt high temperature viscosity reducer is prepared by raw materials of, by mass, 100 parts of oxidized polyethlene wax, 5-40 parts of higher fatty acid and 10-50 parts of metal hydroxide. The rubber asphalt high temperature viscosity reducer is simple in preparation process, convenient to use and capable of reducing high temperature viscosities of ordinary rubber asphalt and modified rubber asphalt and reducing rubber asphalt intermolecular surface tension so that mixing temperatures of rubber asphalt mixtures are reduced, and purposes of reducing energy consumption and protecting environment are achieved.