Flower cluster-shaped ZnO microstructures have been successfully synthesized by a facile hydrothermal approach without further heat treatment using Zn(NO 3 ) 2 . 6H 2 O and NaOH as raw materials and sodium lignosulfonate (SL) as a structure-directing agent. The morphology, structure, and property of the products were characterized by X-ray powder diffraction, fourier transform infrared spectroscopy, scanning electron microscopy, Brunauer-Emmett-Teller nitrogen adsorption-desorption isotherms and photoluminescence spectrum. The photocatalytic activity of the as-prepared samples were evaluated by photocatalytic decolorization of methylene blue aqueous solution at ambient temperature. The results indicated that the prepared ZnO-SL sample exhibited flower clustered morphology, hexagonal wurtzite structure, higher surface areas and better UV and visible photocatalytic activity. Moreover, the ZnO-SL sample showed excellent stability after three photodegradation cycling runs.