The　subsurface　damage　has　a　siginificant　effect　on　the　strength　of　the　wafer.　To　investigate　the　effect　of　the　grinding　speed　and　depth　of　cut　on　the　surface　and　subsurface　damage,　a　series　of　large　scale　MD　simulation　of　nano　grinding　of　silicon　is　performed.　The　results　show　that　the　monocrystalline　silicon　lattice　undergoes　extrusion　and　shear　deformation,　lattice　reconstruction　and　amorphous　phase　transformation　are　also　observed　during　the　grinding　process.　It　also　turned　that　the　grinding　speed　has　an　optimal　value　approximately　160m/s　in　the　range　of　50-400　m/s.　By　considering　the　variation　of　subsurface　damage　thickness　for　various　depths　of　grinding　at　the　grinding　speed　of　160m/s.　The　results　show　that　the　subsurface　damage　are　gradually　increasing　from　9.5　angstrom　to　20.5　angstrom　with　the　augment　of　the　depth　of　cut　from　5　angstrom　to　30　angstrom.　Based　on　the　above　conclusions,　it　can　be　predicted　that　smaller　depth　of　cut　could　reduce　subsurface　damage.