The invention provides a high selectivity catalyst used for catalyzing and completely oxidizing formaldehyde with low concentration at room temperature. The catalyst can catalyze formaldehyde completely so as to lead the formaldehyde to be converted into carbon dioxide and water at room temperature. In addition, the conversion rate of formaldehyde remains 100% within a long period of time, without complex auxiliary facilities such as light source, a heating oven and the like, and external conditions. The catalyst comprises three parts which are inorganic oxide carrier, noble metal component and auxiliary ingredient. Porous inorganic oxide carrier is one of cerium dioxide, zirconium dioxide, titanium dioxide, aluminium sesquioxide, tin dioxide, silicon dioxide, lanthanum sesquioxide, magnesium oxide and zinc oxide or the mixture thereof or composite oxide thereof, zeolite, sepiolite and porous carbon materials. The noble metal component of the catalyst is at least one of platinum, rhodium, palladium, gold and silver. The auxiliary ingredient is at least one of the alkali metals of lithium, sodium, kalium, rubidium and cesium. The loading of the noble metal component used in the catalyst of the invention is 0.1 to 10% according to weight converter of metal elements and the selective preference is 0.3 to 2%. The loading of the auxiliary ingredient is 0.2 to 30% according to weight converter of metal elements and the selective preference is 1 to 10%. When the loading of the auxiliary ingredient is lower than 0.2% or higher than 30%, the activity of the catalyst for catalyzing and oxidizing formaldehyde at room temperature is decreased remarkably.