Flower-shaped Zno nanostructures have been successfully fabricated via the oxidation of metallic Zn powder mixed with some Sri powder. Investigation results demonstrate that the ZnO flowers are made up of nanorods, nanosaws, or double-sided nanocombs. And all of these nanostructures are single crystal of wurtzite hexagonal phase. For the formation of such ZnO flower structures, the additive of tin powders is very important. They could be evaporated and oxidized to SnOx to affect the growth action in the experiment process. A possible mechanism has been supposed here to explain this phenomenon. Finally, the corresponding room-temperature photoluminescence has also been discussed in the paper. (c) 2007 Elsevier B.V. All rights reserved.