Flower-like ZnO structures with high photocatalytic performance were successfully synthesized via a facile hydrothermal method. Alkaline environment played a critical role during the morphological transformation. When the molar ratio of Zn(CH3COO)(2)center dot 2H(2)O to NaOH was set as 1:8 in the presence of triethanolamine (TEA), and the molar ratio of Zn2+ to TEA was 1:9, the flower-like ZnO product was produced. The hexagonal sphere-like, oblate-like, and hexagonal biprism-like samples were also obtained by adjusting the molar ratio of Zn2+ to NaOH as 1:2, 1:5 and 1:12 with the presence of invariable amount of TEA, respectively. The prepared ZnO products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Brunauer-Emmett-Teller (BET) surface area. Photodegradation experiments of the samples were carried out by choosing Methylene Blue (MB) as a model target under UV irradiation with homemade photocatalytic apparatus. Among these products, flower-shaped samples exhibited the highest photocatalytic activity. (C) 2012 Elsevier B. V. All rights reserved.