The invention relates to a preparation method for a Pt-Zr modified aluminide coating. The preparation method comprises the following steps that surface treatment is carried out, pure Zr particles with the grain size ranging from 0.1 micron to 10 microns are added into conventional platinum plating bath, and a magnetic stirring instrument is used for stirring a mixed solution until even suspension is formed; the electroplating condition is set, wherein a Pt-Zr composite Pt-Zr method is adopted, in the process that an Zr element is led into the coating, except for basic electroplating equipment, the magnetic stirring instrument is led in to stir the solution, and the solution keeps to stay in the suspension state; electroplating solution maintenance is carried out, wherein Zr fine grains are added, a target platinum plating solution is supplemented, and the pH value is adjusted; a composite platinum plating is obtained after electroplating and is subject to annealing in a vacuum annealing furnace; and embedding, slurry and CVD chemical vapor deposition alumetizing are adopted, and the Pt-Zr modified high temperature protection aluminide coating is obtained. The preparation method has the beneficial effects that the method is easy, convenient and quick, and saves cost; meanwhile, the contents of the Pt and Zr contents are controllable, and distribution is even; and requirements for workpiece shape and size are avoided, and the service life of an engine blade component is obviously prolonged.