Cluster-like 4ZnO center dot B2O3-H2O nanostructure and 4ZnO center dot B2O3 center dot H2O nanoribbon have been prepared under hydrothermal conditions at 120 degrees C for 12h. All the samples were characterized by the X-ray powder diffraction (XRD), infrared spectrum (IR), and energy dispersive X-ray spectroscopy (EDS). The sizes and morphologies of the products were investigated by scanning electron microscope (SEM) and transmission electron microscope (TEM). The results show that 4ZnO center dot B2O3 center dot H2O cluster consists of nanoribbons with the thickness of about 80 nm and the width of 200-300 nm. 4ZnO center dot B2O3 center dot H2O nanoribbon is about 50 nm in thickness and about 200-500 nm in width. The flame retardant properties of the prepared 4ZnO center dot B2O3 center dot H2O nanomaterials were investigated by the thermal analysis method and a vertical combustion test, demonstrating that they had the better behaviors than the non-nanostructure sample. (C) 2010 Elsevier B.V. All rights reserved.