Abstract: A combined structure made of a foam material includes a top panel, two long side panels, two short side panels, and a bottom panel, wherein the top panel at its bottom has a plurality of slots, and the long side panel at its top has two protruding tenons for engaging the slots, and the long side panel includes two penetrating groove holes on both sides for embedding the protruding tenons, and the long side panel at its bottom has a plurality of protruding tenons for fixing the slots at the corresponding positions at the periphery of the bottom panel. The foam material forms a table or a chair capable of storing articles, so as to achieve the effects of providing a convenient and quick installation, a light weight, an easy storage, and a feature of not occupying too much space after the combined structure is disassembled.