The meso-macroporous hierarchical CuO microspheres composed of nanosheets were prepared by a simple solvothermal method combined with post-annealing. The samples were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high resolution transmission electron microscope (HRTEM) and Brunauer-Emmett-Teller N-2 adsorption-desorption analyzes. The results reveal that the meso-macroporous hierarchical CuO microspheres are monoclinic structure and are assembled by porous nanosheets. The Brunauer-Emmett-Teller N-2 adsorption-desorption analysis indicates that the as-prepared meso-macroporous hierarchical CuO microspheres have a surface area of 42 m(2) g(-1) with pore size of 8-60 nm. The meso-macroporous hierarchical CuO microspheres exhibited a low working temperature and excellent response, especially to the low concentration of ethanol. The response of the meso-macroporous CuO microspheres composed of porous nanosheets to 100 ppm ethanol reached 13.7 at a working temperature of 150 degrees C. The enhancement of the response was attributed to the large specific surface area and thin platelet-like building blocks. (C) 2013 Elsevier B.V. All rights reserved.