The　effect　of　the　grain　boundary　(GB)　misorientation　on　plastic　deformation　of　Inconel　718　(IN718)　alloy　was　investigated　in　this　paper,　using　in-situ　tensile　experiment　at　650 °C　in　combination　with　crystal　plasticity　finite　element　method　(CPFEM).　The　results　indicate　that　dislocations　tend　to　accumulate　at　GBs　to　form　stress　concentration,　but　the　degree　of　stress　concentration　does　not　necessarily　increase　with　the　increase　of　the　GB　misorientation.　It　is　attributed　to　the　slip　transfer　at　the　GBs,　determined　by　the　angle　between　the　slip　systems　of　the　two　adjacent　grains.　There　is　a　significant　uncertainty　in　the　slip　transfer　for　GB　misorientation　larger　than　10°.　However,　the　mαβ′SFα+SFβ　criterion,　which　is　a　function　of　the　Luster　and　Morris　mαβ′　combining　the　Schmid　factors　of　the　two　slip　systems　with　the　GB　misorientation,　has　some　statistical　separation　significance.　Slip　transfer　tends　to　appear　at　GB　misorientation　less　than　30°　and　mαβ′SFα+SFβ＞0.78.　This　study　clarifies　the　mechanism　of　the　influence　of　GB　misorientation　on　IN718　microplastic　deformation　and　provides　a　new　strategy　to　study　the　deformation　behavior　of　superalloys.　©　The　Author(s),　under　exclusive　licence　to　Springer　Science+Business　Media,　LLC,　part　of　Springer　Nature　2024.