In the present study, a novel hydrophobic/hydrophilic polystyrene/polyamide interpenetrating polymer network (PS/PAM IPN) was synthesized and its molecular structure was characterized by Fourier transform infrared ray (FT-IR) spectrum, chemical analysis, swelling test, and N-2 adsorption-desorption experiment. The obtained PS/PAM IPN was employed as a polymeric adsorbent to adsorb quercetin from aqueous solution, and the adsorption thermodynamics were calculated according to thermodynamic equations. It was found that no chemical bond was formed between PS and PAM and PS/PAM IPN held characters of amphiphilic polymer network (APN). The adsorption isotherms could be well fitted by Freundlich isotherm, and the adsorption was shown to be an exothermic, spontaneous, and more ordered process. The total adsorption capacity from the column adsorption experiment was measured to be 8.6 mg/mL wet resin, and the adsorbed quercetin on PS/PAM IPN could be easily desorbed by 10% of hydrochloric acid-ethanol. (C) 2010 Wiley Periodicals, Inc. J Appl Polym Sci 118: 3643-3648, 2010