In　order　to　accurately　measure　the　internal　stress-strain　curve　of　plain　concrete　specimens　and　confined　concrete　specimens　under　compression,　a　new　measurement　method　is　proposed,　which　adopts　conventional　strain　gauges　to　measure　the　internal　strain　data　of　the　specimens,　and　the　micro　soil　pressure　box　with　ultra-large　range　is　developed　to　measure　the　internal　stress　of　the　specimens.　The　uniaxial　compression　tests　of　3　plain　concrete　specimens　and　9　confined　concrete　specimens　are　completed,　and　the　macroscopic　failure　process　of　the　specimens　and　the　stress-strain　curves　at　different　internal　points　are　obtained.　Combined　with　the　experimental　results,　the　accuracy　of　the　calculation　results　of　several　classical　confined　concrete　constitutive　models　is　compared,　and　a　modified　constitutive　model　is　proposed.　Solid　finite　element　analysis　is　used　to　analyze　the　stress-strain　curves　at　different　points　inside　the　specimens,　and　the　prediction　accuracy　of　different　constitutive　models　is　compared.　On　this　basis,　nonlinear　finite　element　analysis　is　used　to　verify　the　quasi-static　test　of　RC　columns,　and　the　accuracy　of　different　constitutive　models　in　the　nonlinear　analysis　at　the　component　level　is　compared　and　analyzed.　The　results　show　that　the　measurement　method　proposed　in　this　study　can　accurately　measure　the　stress-strain　data　internal　the　concrete.　The　calculation　results　of　the　modified　constitutive　model　proposed　in　this　study　are　in　the　best　agreement　with　the　test　results,　and　have　a　wide　range　of　applications,　which　can　be　applied　to　the　measurement　of　internal　stress-strain　curves　of　other　different　types　of　specimens.　©　2024