CdS:Y3+ nanobelts were synthesized by thermal evaporation method. These synthesized nanobelts were characterized with scanning electron microscopy (SEM), X-ray diffraction (XRD) and photoluminescence spectroscopy (PL). SEM images show that each nanobelt has a flat and smooth regular surface with a width of between 5 and 15 micrometers. A typical thickness of these nanobelts is in the range of tens of nanometers. XRD pattern confirmed that nanobelts are hexagonal wurtzite structure with lattice constants a = 0.414 nm and c = 0.671 nm. Photoluminescence spectra of the nanobelts revealed that emission bands centered at 395、436、467、481、491、520 and 585 nm respectively.