The chemical adsorption of dissolved oxygen (DO) by co-oxide filter film-coated sands, formed through the filtration of ground water containing high concentrations of ammonia, manganese and iron, were studied. The results showed that the filter film consisted of silicates, carbonates, manganese and iron oxides and was constructed in a three-layer porous structure. The specific area of film-coated sands was 6.5 m2/g. The chemical adsorption sites of DO are composed of silicates, iron and manganese atoms, and the adsorption was a weak chemical effect. The O2− is the adsorbed species of DO.