It is valuable for the house designer to be aware of a structure's acoustic performance from its material properties at the design stage. A simplified calculation procedure is necessary for this purpose. This report concerns the application of a homogeneous plate prediction model in determining the impact sound insulation for the lightweight steel framing floors. The method is a further development of a prediction method for timber floors. In order to calculate driving point impedance of the lightweight steel framing floor, an equivalent method is used in this study to obtain the parameters of the composite lightweight steel framing floor, e.g. floor height, material density and elasticity to replace a composite floor with a homogeneous single plate. The main advantages of this method will be its simplicity and improve the understanding of the impact sound insulation of the lightweight steel framing floors. This method can also give brief information about the acoustic performance of the structure at an earlier design stage.