A new type of water-soluble polymer, sulphonated acetone-formaldehyde resin (SAF), was developed as dispersant for the preparation of highly-loaded coal water slurry (CWS). In this study, in order to evaluate the practical use in industry, the SAF and a naphthalene sulfonate formaldehyde condensate are used to prepare CWS using four Chinese coals with different coalification degrees. The evaluation of the properties of CWS shows that SAF has better ability in reducing CWS viscosity at lower dosage than naphthalene sulfonate formaldehyde condensate, and that the CWS prepared from SAF has excellent stability within 48 h and exhibits shear-thinning apparent viscosity/shear rate behavior at lower dosage. Based on the results, the SAF is an effective and promising dispersant for highly-loaded CWS. (c) 2006 Elsevier Ltd. All rights reserved.