An urchin-like ZnO/MgO hierarchical structure was synthesized successfully via one-step thermal evaporation of the mixture of metal Zn and Mg powders under designed conditions. The morphology observations and structure analysis of ZnO/MgO hierarchical structures and the related byproducts revealed that there existed a morphology evolution linkage as MgO spheres - ZnO/MgO hierarchical structures -ZnO flowers. The detailed investigations suggested that the temperature and ZnOx concentration in gas flow played crucial roles in the formation of these structures, especially for the hierarchical structure. The photoluminescence spectra showed a regular change corresponding to the morphology evolution. (C) 2007 Elsevier B.V. All rights reserved.