In　this　paper,　the　mechanical　properties　and　microstructure　evolution　of　Ni　based　single　crystal　superalloy　with　different　secondary　orientations　under　stress　loading　were　studied　by　molecular　dynamics　(MD)　simulation.　The　MD　model　is　a　supercell　structure　established　with　three-dimensional　cubic　mosaic　units,　and　the　volume　fraction　of　the　?＇precipitated　phase　is　65%,　which　is　similar　to　the　structure　of　the　actual　material.　The　effect　of　secondary　orientation　on　the　tensile　properties　of　superalloy　was　analyzed　on　the　atomic　scale,　and　the　mechanism　of　the　secondary　orientation　on　tensile　deformation　and　fracture　was　discussed　systematically.　The　work　in　this　paper　will　be　helpful　to　understand　the　tensile　deformation　behavior　of　superalloy　from　an　atomic　point　of　view.　©　Published　under　licence　by　IOP　Publishing　Ltd.