Selenium nanoparticles (SeNPs) with strong green scattering light serving as light scattering nanoprobes for dark-field microscopy imaging are developed for the first time. The SeNPs show good stability, excellent biocompatibility, and high light-producing power, and can precisely and specifically target cancer cells with overexpressed nucleolin (NCL) after modification with aptamers, revealing that the SeNPs can act as a good light scattering nanoprobe for bioimaging and biolabeling.