In this study, polyetherimide with pellet state was sulfonated with a chlorosulfonic acid. The volume ratio of carbon tetrachloride (CCI$_4$/1,2-dichloroethane (DCE) was 5/1. Therefore, sulfonated polyetherimide of anionic charge and more hydrophilicity were produced. The optimum reaction conditions of sulfonation were that PES/CSA mole ratio was I/I, temperature were lO$^{circ}$ and reaction time were 3hr. SPEls having ion capacity in the range of 0.2-1.2meq/mg were synthesized. Through FT-IR, sulfonic acid peak was shown at 1020cm$^{-1}$ and 1170cm$^{-1}$ Polymer dispersity index was broad and we confirmed that PEl was hydrophilzed in the measure of contact angle.