Zinc oxide (ZnO) nanostructures with different morphologies such as nanopyramids, nanosheets, and nanoparticles have been grown by a simple solvothermal method. The influence of solution pretreatmentt on the morphology and optical properties of ZnO nanostructures has been studied. The experimental results revealed the morphology of ZnO transformed from nanopyramids or nanosheets to nanoparticles after solution pretreatment. Raman and photoluminescence spectra are recorded to examine the crystallinity and optical property of the samples. © 2013 Wenhui Zhang et al.