Diamond　has　the　highest　thermal　conductivity　and　the　highest　hardness　in　nature,　ultralow　thermal　expansion　coefficient,　becoming　the　typically　fourth　generation　semiconductor.　High-performance　devices　and　chips　stringently　require　atomic-level　surface　of　diamond,　i.e.　surface　roughness　Sa　＜0.2　nm.　This　is　a　challenge　to　achieve　atomic-level　surface　on　the　hardest　diamond　with　ultrahigh　chemical　inertness.　This　review　presents　challenges,　progresses　and　future　directions　of　advanced　atomic-level　polishing　for　single　crystal　diamond.　It　includes　chemical　mechanical　polishing,　ion　beam　polishing,　light-assisted　polishing　and　plasma-assisted　polishing.　The　review　analyses　the　historical　development,　material　removal　mechanisms,　advantages　and　disadvantages　of　these　polishing　methods.　Traditional　polishing　based　on　classical　mechanics　faces　challenges　to　garner　atomic-level　surface.　Future　directions　of　atomic-level　polishing　are　necessary　to　develop　novel　polishing　methods　with　hybrid　energy　fields,　such　as　plasma,　light　and　chemical　fields,　etc.　Cross-scale　coupling　models　of　multi-physics　fields　need　to　be　proposed　to　develop　novel　polishing　methods,　consisting　of　polishing　setups,　optimization　of　processing　parameters,　polishing　pads　and　slurries.　This　review　provides　new　insights　to　acquire　atomic-level　surface　of　diamond　using　advanced　polishing　methods　for　stakeholders　in　education,　academia　and　industries.　©　2025　Elsevier　B.V.