In this study, we suggest a new and efficient technique to convert common waste polystyrene into a functional exchange polymer. Waste polystyrene was crushed into small pieces and immersed in sulfuric acid solution while we varied time, dimension of particles and temperature. It was found that for a temperature above 70°C and period of treatment of 2 hours, waste polystyrene became soluble in acidic solution. Best degree of sulfonation was obtained with samples treated at 60 °C for 2 hour (17.25%) and for 40°C for 4 hours (16.87%). For these samples, we evaluated some exchange properties such as: swelling behavior, wettability and cation exchange properties.