Density gradient ultracentrifugation (DGUC), as an effective method for the purification of nanomaterials, has attracted research. A recent review was reported by Science Bulletin in a paper titled “Density gradient ultracentrifugation for colloidal nanostructures separation and investigation,” by Xiaoming Sun and Liang Luo et al from Beijing University of Chemical Technology. The authors systematically introduce the classification, mechanism and applications of density gradient ultracentrifugation (DGUC) with various separation examples, demonstrating the versatility of such an efficient separation technique.