Characteristics of light fastness for the inorganic phosphates was measured in the form of PVC paste sol, composing of aluminum hydroxide phosphate or magnesium hydroxide phosphate as one portion of flame retardant, using fademeter. Inorganic phosphates, especially metal hydroxide phosphates, have a sort of twin characteristics of the composite, composed by two components, which means a chemically bonded mixture of a metal hydroxide and a phosphoric acid. The degree of whiteness for the PVC paste sol including inorganic salts were shown relatively good results than that of the PVC paste sol including a brominated compounds.