Water-soluble multi-walled carbon nanotubes (MWNTs) with a high solubility of 29.2 mg ml(-1) were obtained by polymer dispersant hydrolyzed poly(styrene-co-maleic anhydride) (HSMA) assisted exfoliation and centrifugation. The MWNTs were exfoliated and dispersed in aqueous solution by non-covalent modification with polymer dispersant of HSMA. Characterizations of HSMA-coated MWNTs were conducted via transmission electron microscopy (TEM), UV-vis and fluorescence spectroscopy, and thermal gravimetric analysis (TGA). The as-prepared HSMA-coated MWNTs showed good dispersibility and stability in water.