In　the　current　study,　a　multiaxial　LITS　model　of　concrete　was　innovatively　developed.　This　model　can　predict　the　behavior　of　concrete　subjected　to　wide　applied　load　level　ranges　from　20　%　to　80　%　and　temperatures　up　to　800　degrees　C.　A　3D　LITS　model　is　developed　through　a　triaxial　compression　stress　confinement　implementation　and　Poisson＇s　ratio.　Considering　the　water　evaporation　of　concrete　under　high　temperature,　a　third　order　polynomial　LITS　derivative　function　and　an　exponential　derivative　function　were　proposed　to　characterize　the　effects　of　the　stress　confinement　and　thermal　effect.　In　order　to　comprehensively　predict　the　performance　of　concrete　subjected　to　multiaxial　compressive　loads　in　fire,　an　orthotropic　triaxial　compression　thermo-mechanical　damage　model　for　concrete　is　developed.　The　effect　of　LITS　on　the　multiaxial　stress-strain　response　was　considered　in　the　multiaxial　model.　The　coupling　thermo-mechanical　contributions　containing　the　development　of　LITS　among　thermal　effect,　stress　confinement,　damage　and　plastic　hardening　evolution　were　creatively　considered　in　the　potential　function　within　thermodynamics　framework.　The　numerical　calculations　of　this　proposed　model　were　conducted　for　validation.　The　effect　of　LITS　on　the　multiaxial　stress-strain　response　was　studied.　The　nonlinear　stress-strain　responses　of　concrete　were　accurately　captured　at　temperatures　ranges　from　20　degrees　C　to　1000　degrees　C　through　the　comparative　study　with　test　results　in　literatures,　which　indicates　the　accuracy　and　applicability　of　the　proposed　model.