The invention belongs to the field of inorganic non-metallic material preparation and relates to a preparation method of an yttrium chromate spherical hierarchical structure. The preparation method comprises fully dissolving yttrium acetylacetonate and chromic nitrate in a methanol solution, carrying out a solvent thermal reaction process, filtering and washing the product, and drying, calcining and cooling the product to obtain the yttrium chromate spherical hierarchical structure. The preparation method has the advantages of simple process, high product purity and low preparation cost. The yttrium chromate spherical hierarchical structure big ball has a size of 2 to 3mm and a component particle size of 50 to 100nm. The product has good uniformity and dispersibility. The preparation method is simple, has a low sintering temperature and is easy to use in to actual large-scale production.