ZnO nanosheets (see Figure) are fabricated by a physical vapor-transport technique. Temperature-dependent microphotoluminescence spectroscopy is conducted from 80-857 K. A surprisingly strong high-temperature (857 K) photon emission is observed. A brief discussion is given in an attempt to understand the physical mechanisms. Technically, this finding demonstrates that the ZnO nanostructure has a potential for high-temperature optoelectronic applications.