Through noncovalent modification of multi-walled carbon nanotubes (MWNTs) with the dispersant of sodium dodecyl sulfate (SDS), ZnO nanocrystals-coated MWNTs composite was fabricated. The electrostatic interaction mechanism is used to illustrate the formation of ZnO/MWNTs nanocomposite. The ZnO-coated MWNTs composite shows a small blue-shift absorption compared with pure ZnO nanomaterial and preserves the electronic energy states of MWNTs. The photocatalytic experiments exhibit that this composite has a higher photocatalytic activity than ZnO bulk material or the mechanical mixture of MWNTs and ZnO. (c) 2004 Elsevier B.V. All rights reserved.