The　ultrasonic　vibration-assisted　polishing　(UVAP)　method,　a　recently　developed　advanced　processing　technology,　is　widely　used　in　the　processing　of　brittle　materials.　This　study　uses　molecular　dynamics　(MD)　simulations　to　investigate　the　polishing　behavior　of　diamond　grits　on　SiC　workpieces　during　the　UVAP　process.　The　frequency　(fz),　amplitude　(Az),　and　dimensions　of　the　vibration　are　varied　to　investigate　various　aspects　of　the　material　removal　process.　In　the　low-frequency　region,　the　UVAP　processing　method　exacerbates　taper　slips　and　dislocations　in　the　workpiece.　In　the　high-frequency　region,　fz　and　Az　can　improve　the　MRR　by　more　than　32%　and　reach　2–4　times　higher　than　that　of　traditional　scratching,　respectively.　The　surface　morphology　obtained　using　MD　simulation　is　consistent　with　the　experimental　results.　In　the　ultrasonic　elliptical　vibration　assisted　polishing　(UEVAP)　method,　fy　not　only　causes　a　periodic　and　stable　increase　in　temperature,　which　helps　to　transform　atoms　into　an　amorphous　structure,　but　it　also　increases　material　removal　rate　(MRR)　while　decreasing　friction　factor　and　surface　roughness.　Appropriate　increase　of　fz　reduces　forces　and　improves　stress　distribution.　Az　significantly　increases　MRR　but　results　in　a　rough　surface.　In　comparison　to　the　UVAP　process,　the　UEVAP　method　further　improves　MRR　and　produces　smoother　machined　surfaces.　Graphical　Abstract:　This　study　uses　molecular　dynamics　(MD)　simulations　to　investigate　the　polishing　behavior　of　diamond　grits　on　SiC　workpieces　during　the　UVAP　process.　The　frequency　(fz),　amplitude　(Az),　and　dimensions　of　the　vibration　are　varied　to　investigate　various　aspects　of　the　material　removal　process.　(Figure　presented.).　©　The　Author(s),　under　exclusive　licence　to　Springer　Science+Business　Media,　LLC,　part　of　Springer　Nature　2024.