In this study, we report a simple sol-gel electrophoretic deposition method for growing two different morphologies of ZnO using triethylamine (TeA) and diethanolamine (DEA) as stabilizers in order to systematically investigate the importance of morphological and structural properties on photocatalytic applications of ZnO. FESEM imaging shows that the morphology of the ZnO nanostructured films can be tuned from ZnO urchinlike shapes assembled by nanoparticles to nanoplate arrays-built flower-like hierarchical nanostructures when TeA and DEA are used as additives, respectively, by selecting the appropriate reactants and optimizing the sol concentration, molar ratio of additive to precursor, time, and voltage of deposition. The specific mechanisms for the formation of these two morphologies are also proposed based on the observation of time-dependent experiments. The large specific surface area of flower shapes compared to urchins result in enhanced absorption of methylene blue and improved photocatalytic activity.