Abstract: ZnS nanocrystal/CNT composite films were synthesized by the reaction of Na2S with Zn(NO3)2 in an aqueous solution containing CNTs purified by 65% HNO3. The composite films were characterized by transmission electron microscopy, X-ray diffraction, selected area electron diffraction and energy dispersive X-ray spectroscopy. Results show that the CNTs act as the framework of the composite films and the ZnS nanoparticles are either anchored on the surface of the CNTs or filled apertures in the CNT network. The ZnS nanoparticles have a well-crystallized wurtzite structure and a uniform diameter of around 5nm. The ZnS/CNT composite is expected to improve the photocatalytic ability of ZnS due to the unique conductive and wave absorptive properties of the CNTs.