Large-scale, uniform ZnO nanocones with tips about 200 nm and length about 50 pin have been synthesized by a facile hydrothermal method. The morphology and structures were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM). transmission electron microscope (TEM) and hi.-h-resolution transmission electron microscope (HR-TEM). The effects of reaction time and PEG-400 on the morphology of ZnO nanostructures were investigated, also an oriented attachment mechanism has been briefly proposed. The optical properties were investigated by lasing confocal microscope and photoluminescence spectrum, a strong near band edge emission peak centered at 387 nm from the ZnO nanocones was observed in photoluminescence spectrum. Finally, we have fabricated UV photodetector based on single ZnO nanocone, which present good switching properties by turning the UV light on and off. (C) 2008 Elsevier Ltd. All rights reserved.