Abstract CuO as-prepared samples were prepared at room temperature using the mixed water–ethanol solvents. After hydrothermal treatments on these samples at high temperatures, CuO nanorods were controlled to have surface areas ranging from 72.1 to 7.2 m 2 g −1. All CuO nanorods were characterized by X-ray diffraction (XRD), thermogravimetric (TG) analysis coupled with differential thermal analysis (DTA), transmission electron microscope (TEM), Brunauer–Emmett–Teller (BET) technique, and Fourier transformation infrared spectroscopy (FTIR). CuO nanorods showed a surface hydration which was increased with decreasing the surface area. CuO nanorods were studied as an additive for promoting the thermal decomposition of ammonium perchlorate (AP). With the addition of CuO nanorods, thermal decomposition temperature of AP decreased. Large surface areas of CuO nanorods promoted AP decomposition, while surface hydration did not have any apparent influence. These observations were explained in terms of the surface O 2− species that accelerate the proton transfer in AP decomposition.