Mass production of US nanobelts is successfully achieved by a simple thermal evaporation of US powders under controlled conditions in the presence of Au catalysts. The as-synthesized US nanobelts are single-crystalline with wurtzite structure, usually several hundred nanometers in width, tens of micrometers in length, and tens of nanometers in thickness. The room-temperature photoluminescence spectrum of US nanobelts features three luminescence peaks around 504, 5 13, and 770 nm, which are attributed to the band-edge, band-to-band and surface state emissions, respectively. The growth of CdS nanobelts is initiated by Au catalyst nanoparticles via a catalyst-assisted vapor-liquid-solid process, and a side growth along the belt width direction via a vapor-solid process is also suggested. This synthetic method offers the possibility for the control of US nanobelts on a special substrate, which would be of particular interest for their applications in optoelectronic devices.