The　microscopic　molecular　motion　behavior　between　graphene　and　the　liquid　lubricant　oil　affects　the　rheological　and　frictional　behavior　of　the　nano-lubricant.　However,　the　effect　of　graphene　on　the　rheological　behavior　of　industrial　#3　lubricant　oil　has　not　been　revealed.　Thus,　molecular　dynamics　(MD)　and　experimental　study　are　used　to　investigate　the　effect　of　graphene　concentration,　size,　temperature,　and　shear　rate　on　the　viscosity,　mean　square　displacement　(MSD),　and　density　of　graphene　lubricant　oil　are　investigated.　The　results　show　that　the　viscosity　of　GLO　increases　with　the　increase　of　graphene　concentration　and　decreases　with　the　increase　of　temperature　(293　K–330　K).　The　MSD　of　graphene　lubricant　oil　decreases　with　the　increase　of　graphene　size　and　increases　with　the　increase　of　temperature.　It　is　worth　noting　that　graphene　lubricant　oil　with　3G　has　the　maximum　value　of　MSD,　which　means　the　graphene　has　the　best　diffusion　performance　at　this　concentration.　Compared　to　the　base　oil,　the　simulation　and　experiment　viscosity　values　of　the　GOL　with　3G　increased　by　22.9　%　and　47.6　%,　respectively.　The　GOL　has　the　characteristics　of　a　Newtonian　fluid.　This　study　can　provide　a　reference　for　the　application　of　graphene　lubricant　oil　in　industry.　©　2023　Elsevier　B.V.