A series of 1.5-2 mu m Pt/Bi2WO6 composite microflowers (mass concentration: 0.5%Pt, 1%Pt, 2%Pt, 4%Pt) assembled by Bi2WO6 nanosquares were synthesized by a hydrothermal synthesis combination with photo-deposition method. The as-synthesized microflowers were investigated by photocatalytic reaction and characterized by powder X-ray diffraction (XRD), N-2-physical adsorption, scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV-Vis diffuse reflectance spectra (DRS), X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FT-IR). The results showed that these hierarchical Pt/Bi2WO6 composite microflowers have superior texture property in aqueous photocatalytic reactions. Moreover, the deposited Pt nanoparticles (NPs) play an important role in promoting the photocatalytic performance in degradation of acid orange II under visible light (lambda > 420 nm) irradiation. The deposition of optimal amount of 1%Pt brings about 2.8 times increase in activity. The deposited Pt NPs over Bi2WO6 nanosquares enhance the visible light absorption, decrease the recombination rate of e(-)/h(+) pairs and promote (OH)-O-center dot radicals production, hence largely boosting the photocatalytic activity. Moreover, the unique hierarchical structures of Pt/Bi2WO6 microflowers benefit their separation and recycle in aqueous photocatalytic reactions. (C) 2015 Elsevier B.V. All rights reserved.