The invention provides a copper-zinc-aluminum catalyst for preparing methanol through hydrogenization of CO2 and having high activity and high hydrothermal stability, and a preparation method of the copper-zinc-aluminum catalyst, and belongs to the technical field of catalysts. The catalyst consists of CuO, ZnO, Zn-Al hydrotalcite and a molding agent. The preparation method comprises the following steps of firstly enabling a Cu-Zn mixed nitrate solution and a parent precipitant solution to be subjected to a precipitation reaction, and after the precipitation of a parent is finished, performing stirring and ageing for 1h so as to obtain parent slurry; then enabling a Zn-Al mixed nitrate solution and a carrier precipitant solution to be subjected to a precipitation reaction, and after the precipitation of a carrier is finished, treating the obtained carrier precipitate in a closed container so as to obtain carrier slurry; mixing the carrier slurry with the parent slurry, after the mixing is finished, washing ternary slurry, performing solid-liquid separation, drying the obtained ternary precipitate, performing temperature programmed calcination, and adding the molding agent for shaping so as to obtain the catalyst. The catalyst has high catalytic properties and hydrothermal stability.