A novel filter media-grain slag as filter media for the removal of phosphorous studied in the paper. The characteristics of grain-slag and haydite such as total porosity, total surface area, pore size distribution, apparent and bulk density, crystal structures and chemical composition were evaluated for the two materials firstly. The data of pore characteristics and surface morphology of filter materials showed grain-slags were superior to haydites in many ways, including higher total porosity, larger total surface area and lower density. These characteristics were essential for filter materials. Subsequently, the pH of solution and contact time was evaluated in batch phosphate sorption experiments for the two materials. The results showed the phosphate removal rate of grain-slag was higher than haydite. The phosphate removal of the grain-slag tended to decrease with increasing initial pH above neutral. Therefore, grain-slag application, as a novel process of treating phosphorus with wastes, provided a promising way in grain slag utilization.