Microstructure,　mechanical　performances　at　elevated　temperature　(650　degrees　C)　and　their　correlation　of　Inconel　718　manufactured　by　Selective　Laser　Melting　(SLM)　were　investigated　in　this　paper.　Four　kinds　of　heat　treatment　schemes　including　homogenization,　solution　treatment　and　conventional　aging　process　were　carried　out　to　regulate　the　microstructure　in　order　to　obtain　the　optimum　comprehensive　mechanical　performances　at　high　temperature.　The　dimension　and　morphology　of　grains,　subgrains,　different　precipitates　including　delta　phase,　strengthening　phase,　carbides　and　nitrides　were　investigated.　In　addition,　their　evolution　mechanism　was　also　analyzed　in　detail.　Furthermore,　for　figuring　out　the　effects　of　microstructures　on　the　mechanical　performance,　creep　rupture　test　and　tensile　test　were　carried　out　to　compare　the　performance　differences　of　heat-treated　samples.　The　results　demonstrated　that　the　heat-treated　samples　show　the　better　creep　rupture　performance　and　higher　tensile　strength　at　elevated　temperature　than　that　of　the　wrought.　In　addition,　the　sample　under　homogenization　heat　treatment　in　1080　degrees　C,　solution　treatment　in　980　degrees　C　and　conventional　aging　treatment　shows　the　optimum　mechanical　properties　at　650　degrees　C.