Complex　thermal　cycles　and　stress　fields　commonly　occur　in　the　selective　laser　melting　process　for　nickel-based　superalloys,　which　are　prone　to　generating　cracks　and　decreasing　the　performance　of　forming　parts.　In　this　paper,　the　reasons　for　cracking　were　analyzed　by　combining　the　experiment　with　the　evolution　behavior　of　the　temperature　field/stress　field　during　the　solidification　process　of　a　nickel-based　superalloy　(FGH96)　via　a　three-dimensional　finite　element　thermo-mechanical　coupling　model.　It　showed　that　a　radial　temperature　distribution　of　the　melting　pool　led　to　a　similar　distributed　stress;　as　a　result,　the　value　declined　slowly　along　the　scanning　direction　but　declined　quickly　along　the　direction　perpendicular　to　the　scanning　direction.　A　stress　concentration　with　maximum　stress　up　to　339　MPa　was　found　at　the　center　of　the　molten　pool,　easily　causing　a　crack　in　SLM.　It　was　found　that　both　the　initiation　and　propagation　of　the　cracks　were　along　the　grain　growth　direction　and　were　affected　by　the　epitaxial　growth　of　columnar　crystals.　For　the　case　of　process　parameters　with　relatively　high　power　or　low　scanning　speed,　the　stress　value　of　the　molten　pool　during　solidification　was　more　than　370　MPa　so　as　to　form　a　large　area　of　cracks.　The　adjustment　of　the　rotation　angle　between　the　adjacent　layers　was　effective　at　avoiding　stress　accumulation　in　the　building　direction　and　prevent　the　formation　of　long　grain　boundaries,　thus　avoiding　crack　propagation.　The　present　study　lays　a　foundation　for　the　wide　applications　of　selective　laser　melting　technologies　in　nickel-based　superalloys.