Nickel-based　GH3536　alloy　exhibits　high　strength　but　low　ductility　when　produced　by　selective　laser　melting　(SLM),　which　hinders　its　widespread　application　in　aerospace.　This　paper　employed　a　‘two-step’　method　of　heat　treatment　to　optimize　the　microstructure　of　the　SLM　GH3536　alloy　and　investigated　the　mechanical　properties.　Tensile　tests　were　conducted　on　SLM　GH3536　alloy　before　and　after　heat　treatment　at　750　°C,　using　an　in-situ　high-temperature　tensile　stage.　The　relationship　between　the　microstructural　evolution　and　deformation　behavior　of　the　alloys　was　investigated　by　combining　the　in-situ　tensile　experiments　and　crystal　plasticity　finite　element　method　(CPFEM).　The　results　suggested　that　the　elongation　can　be　increased　by　80%　without　a　significant　reduction　in　tensile　strength.　The　improved　elongation　is　attributed　to　the　complete　recrystallization,　formation　of　annealed　twins　and　serrated　grain　boundaries　after　heat　treatment.　The　study　also　investigated　the　deformation　behavior　and　fracture　mode　of　the　alloy　before　and　after　heat　treatment.　Discussion　was　done　on　the　influence　of　the　microstructure,　particularly　the　twin　and　serrated　grain　boundaries　on　the　alloy＇s　plastic　deformation.　This　study　enhanced　the　understanding　of　plastic　deformation　of　SLM　GH3536　alloy　and　provided　a　valuable　reference　for　the　design　and　post-treatment　of　superalloy.　©　2024