Abstract: Nano-ZnO powders with diameters of 8 to 130 nm were prepared from zinc nitrate and urea by homogeneous precipitation method. The precursors in different sizes and with rod-like or lamellar shapes were obtained by controlling the reaction procedures. Then, nano-ZnOof different sizes andwith spherical, net-like and rod-like shapes could be obtained under different calcination conditions. The microstructures and morphologies of the precursors and nano-ZnO particles were analyzed with TEM (transmission electron microscope) and XRD (X-ray diffraction), showing that the shapes and sizes are determined in a great extent by those of the precursors.