Rectangular　shaped　cross-section　316LN　thick-wall　tube,　obtained　from　round　forged　billet　by　extrusion　process,　is　used　in　the　manufacture　of　the　ITER　Top　and　Bottom　Correction　Coil　cases.　The　hot　working　properties　of　316LN　stainless　steel　are　studied　by　compression　test,　stress-strain　curves　and　microstructures　of　samples　at　high　temperature　are　gotten.　FEM　(Finite　Element　Method)　simulation　is　adopted　to　analyze　metal　flow　characteristics　and　optimize　design　of　extrusion　die　in　extrusion　process.　By　billet　forging　and　machining,　extrusion　die　designing　and　manufacturing,　ring-oven　preheating,　induction　heating,　glass　lubrication　and　deformation　designing,　316LN　stainless　steel　rectangle　thick-wall　tubes　are　fabricated　by　60　MN　horizontal　extruder,　the　measurement　and　properties　of　the　products　all　accord　with　the　design　target,　these　products　are　applied　as　structural　support　parts　in　ITER　project　successfully.　(C)　2017　Elsevier　B.V.　All　rights　reserved.