In this work, hierarchical flower-like ZnO nanospheres self-assembled by nanosheets with a thickness of ∼10nm have been synthesized via a simple hydrothermal route together with tetramethylammonium hydroxide (TMAH) and sodium citrate. As TMAH is only used without any sodium citrate, the obtained products are ZnO nanoplates with a thickness of ∼50nm and a lateral size of ∼300nm. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution TEM (HRTEM), and N 2 -physisorption technique were employed to characterize the phase composition and microstructure of the synthesized samples. On the basis of the experimental results, a possible formation mechanism of the ZnO nanoplates and the hierarchical flower-like ZnO nanospheres has been proposed. Due to the ultrathin nanosheet and mesostructure feature, the hierarchical flower-like ZnO nanospheres as anode exhibit significant improvements in reversible capacities and cycle performance over the ZnO nanoplates.