ZnO with hierarchy structure was prepared by a convenient environmental friendly two-step route without using any template. The precursor of Zn(OH)(2) with hierarchy structure was firstly synthesized through an equilibra-shift process. The precursor was then themo-decomposed slowly. The ZnO with the same morphology was obtained. The mechanism for the formation of this structure was elucidated. The low reaction temperature and slow reaction rate favored the hierarchy structure of the precursor. The ZnO showed good photocatalytic activity on degradation of methyl orange under UV light irradiation. (C) 2010 Elsevier B.V. All rights reserved.