The invention discloses a palladium oxide complex for insulated cylinders and a preparation method. The preparation method comprises the following steps: 1), performing a gelatinization reaction on palladium oxide, cyclodextrin and water to obtain a gelatinized system; 2), adding a nickel source, a tin source, neodymium oxide, dysprosium oxide, butyllithium, cetyltrimethylammonium bromide and hydrazine hydrate into the gelatinized system for a hydrothermal reaction, and then filtering and drying to obtain a solidified substance; 3), performing ball milling on the solidified substance to obtainthe palladium oxide complex for the insulated cylinders. The palladium oxide complex for the insulated cylinders can effectively absorb hydrogen; moreover, the preparation method has the advantages of single process and easiness in obtainment of raw materials.