Sulfonated poly(bis[4-(3-aminophenoxy)phenyl]sulfone pyromellite)imide derivatives with various ion-exchange capacities were prepared by heterogeneous sulfonation with chlorosulfonic acid. The effects of sulfonating agent concentration, reaction temperature, and reaction time were investigated. The mechanical and thermal properties, contact angle, change of polydispersity, and solubility were calculated for studying change of their properties. The reactions were effective, when the temperature is <10 degreesC and the concentration of chlorosulfonic acid is between 0.05 and 0.1 M. The value of ion-exchange capacity was increased with reaction time, reaction temperature, and concentration of sulfonating reagent. Thermal and mechanical properties were nearly unchanged according to the degree of sulfonation, but the hydrophilicity indirectly measuring contact angle was increased with increasing the value of ion-exchange capacity.