The invention belongs to the technical field of nanophase material preparation, in particular to faviform nano-spheres of lamellar mesoporous birnessite-manganese-dioxides MnO2 type which are used as catalysts for catalyzing and oxidizing formaldehyde completely under high-efficiency low temperature. The invention takes inexpensive potassium permanganate and oleic acid as reagents with no need of acid or alkali processing, leads redox reaction of the reagents to take place in a neutral aqueous solution, and controls the molar ratio between the potassium permanganate and the oleic acid, thus respectively obtaining monodisperse-faviform nano-spheres and hollow nano-spheres of lamellar mesoporous birnessite-manganese-dioxides. The monodisperse-faviform nano-spheres and the hollow nano-spheres of lamellar mesoporous birnessite-manganese-dioxides of the invention have rich mesopores, bigger specific surface and mesopore capacity, and good structural stability, and can be taken as carriers of catalysts or sorbents, separation materials, magnetic materials, electrode materials of batteries, oxidation and degradation materials, desulfidation or air purification materials, especially as catalysts for catalyzing and oxidizing formaldehyde completely at low temperature.