Flowerlike cadmium sulfide (CdS) nanostructure was prepared via the controllable solvent thermal method by using ethylenediamine as the structure directing template. The synthesized CdS was characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). XRD pattern showed that the flowerlike US nanostructure was a cubic cell. SEM images showed that flowerlike CdS nanostructure is built from dozens of petals. The average crystal size was calculated to be about 3.1 nm. The petals were about 30 nm thick and 1 mu m wide. The specific surface area of flowerlike US nanostructure was found to be 20.77 m(2) g(-1), higher than US powder (10.18 m(2) g(-1)). Photoluminescence (PL) spectrum revealed that US nanostructure had a visible blue emission peak at the wavelength of 433 nm, which arises from the excitonic emission. The photocatalytic activity of CdS was investigated for the decolorization of methyl orange (MeO) under high-pressure mercury lamp illumination. It was observed that the flowerlike CdS showed better results as compared to other CdS materials. (C) 2009 Elsevier B.V. All rights reserved.