Biotemplate-assisted approach is simple and friendly to the environment. With the assistance of gelatin as a soft biotemplate and a structure-directing agent, star-like zinc oxide (ZnO) nanostructures have been prepared by assembly of well-defined nanorods under hydrothermal conditions. Their morphology and structures were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and transmission electron microscopy (TEM). The growth mechanism of the ZnO nanostars is also investigated. The as-prepared ZnO nanostars display high photocatalytic activity toward the degradation of methyl orange (MO) under ultraviolet (UV) irradiation. (C) 2013 Elsevier Inc. All rights reserved.