Abstract: Abstract: The synthesis of nano-onion-like fullerenes on a large scale by the arc discharge method was investigated using Bi2O3 as catalyst. Transmission electron microscopy was used to characterize the morphologies and microstructures of the product. Results indicated that the nano-onion-like fullerenes were perfectly structured and highly graphitized, with uniform external diameter of about 25nm. Two kinds of nano-onion-like fullerenes were obtained: 1) Single-nuclei onion-like fullerenes; 2) Multiple-nuclei onion-like fullerenes. The investigation pointed to a possible routine for large scale synthesis of onion-like fullerenes.