Nanoceria is an important function material and is widely used in catalytic applications due to its excellent redox properties. Here, we report a simple method to synthesize uniform polyhedral nanoceria powder by the KCl-LiCl molten salt method. TEM micrographs of the product showed that polyhedral nanoceria particles of 30 nm average size were obtained from cerium carbonate hydroxide when treated at 600 degrees C for 4 hours. Results indicated that the crystal structure broke down to ceria crystal nuclei in the molten salt system at an elevated temperature, and the Ce3+ dissolved in the KCl-LiCl molten salts provided a cerium source for crystal growth. The crystal and particle sizes increased with treatment temperature. UV-visible absorption results showed that this nanoceria powder had a significant red shift, and its narrow band gap of 2.7 eV suggests a potential application for photocatalysis. The produced nanoceria had a somewhat lower catalytic activity for CO oxidization than commercial nanoceria, mainly due to smaller specific surface area, but had a higher stability.