Abstract: The chemical modification of waste polystyrene(WPS) was summarized in this paper. The modifications could be categorized into two types: (i) The introduction of functional groups to the lateral benzene group of WPS via electrophilic substitution, i.e., sulfonation，halogenation，nitration, chloromethylation, and acylation; (ii) radical copolymerization between the benzyl of WPS and vinyl monomers including acroleic acid, acrylate, maleic, acetate, acrylonitrile, and propenol.

Key words: Expanded polystyrene, chemical modification, Sulfonation, Maleic anhydridition