Copper-doped NaInS2 with hexagonal blocks morphology was prepared by a one-step hydrothermal method and the photocatalytic activity was investigated. The as-synthesized products were characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), and UV-vis spectroscopy. XRD patterns show that the Cu ions doping has no effect on the crystal structure of NaInS2 UV-vis diffuse reflectance spectra show that the absorption wavelength of Cu-doped NaInS2 occurs red-shift which originated from Cu3d orbital forming impurity level. The photocatalytic activity was increased by Cu doping. The optimal doping amount of Cu2+ is 1.5 ml. (C) 2012 Elsevier Ltd. All rights reserved.