The　stress-strain　relation　of　Chinese-made　austenitic　stainless　steel　S31608　(06Cr17Ni12Mo2,　which　is　equivalent　to　AISI　316　and　EN　1.440　1)　and　the　influences　of　welding　and　rolling　directions　were　studying　using　several　types　of　specimens　in　tensile　test　experiments.　The　specimens　were　cut　from　the　base　material　and　from　cross　sections　of　welded　members　with　different　rolling　directions　and　thicknesses.　The　Ramberg-Osgood　equations　as　modified　by　Gardner　and　Nethercot　were　used　to　calculate　the　parameters　for　the　constitutive　relation.　Data　for　different　types　of　specimens　were　compared　to　show　the　influences　of　the　welding　and　rolling　directions.　The　results　show　that　the　stress-stain　relation　for　this　stainless　steel　is　not　linear　and　that　the　R-O　equations　modified　by　Gardner　and　Nethercot　provide　excellent　agreement　with　the　test　data.　The　modulus　of　elasticity　and　the　proof　strength　in　the　longitudinal　direction　are　less　than　that　in　the　transverse　direction.　After　welding,　the　moduluss　of　the　elasticity　increases　while　the　proof　strength　decreases.　The　influences　of　the　welding　and　rolling　directions　on　the　constitutive　relation　should　be　taken　into　consideration　in　engineering　applications.