The invention discloses a simplified baffle layer suitable for IBAD-MgO (ion beam assisted deposition-magnesium oxide) growth on a metal substrate and a preparation method thereof. The simplified baffle layer is arranged on the metal substrate and is a single YAlO baffle layer; and the single YAlO baffle layer is prepared by adopting a multi-channel pulse laser coating technology or a multi-channel magnetron sputtering technology. The YAlO baffle layer with a smooth surface, even surface particle size, low roughness and strong bonding strength is prepared; the YAlO baffle layer can prevent atoms of the metal substrate from diffusing to the other layers, can reduce the roughness of the metal substrate and also can be used as a nucleation layer of an IBAD-MgO layer; the surface roughness of the YAlO baffle layer is smaller than 2 nanometers; the texture degree in the surface of the prepared IBAD-MgO layer is less than 7 degrees; and a rare earth oxide superconducting layer with high performance can epitaxially grow on the baffle layer. By adopting the simplified baffle layer, the quantity of the baffle layers for IBAD-MgO is reduced; simplification, fast speed and low cost of the manufacturing technology are achieved; the simplified baffle layer has high stability, repeatability and reliability, and good application prospect in industry, and is suitable for industrial production.