The　high-entropy　alloys　(HEAs)　primarily　composed　of　elements　such　as　Ti,　Zr,　Hf,　and　Nb　generally　exhibit　a　B2-type　crystal　structure,　contributing　to　their　enhanced　strength.　However,　the　limited　ability　of　the　B2　lattice　structure　to　accommodate　plastic　deformation　leads　to　poor　plasticity　in　this　type　of　alloys.　The　deformation-induced　martensitic　transformation　(DIMT)　occurring　in　the　B2　lattice　can　effectively　alleviate　the　poor　plasticity　associated　with　these　alloys.　Our　work　focuses　on　the　previously　reported　Ti49Zr20Hf15Al10Nb6　high-entropy　alloy　with　DIMT　mechanism,　employing　an　improved　elastic　visco-plastic　self-consistent　(EVPSC)　model　to　predict　and　analyze　the　macro-　and　micro-mechanical　responses　during　uniaxial　tension　and　cyclic　loading　that　includes　loading,　unloading,　and　reloading.　The　model　results　elucidate　the　stress-strain　behavior　and　volume　fraction　evolution　of　the　β　parent　phase　and　α″　martensite　phase　during　tension　and　cyclic　loading,　while　quantitatively　assessing　the　contributions　of　transformation　and　dislocation　mechanisms　to　plastic　deformation.　Additionally,　it　explores　the　influence　of　back　stress—a　topic　that　is　rarely　addressed—on　the　reverse　process　of　martensitic　transformation　and　recoverable　strain　in　this　high-entropy　alloy　at　the　microstructural　level.　This　model　serves　as　a　theoretical　analysis　tool　for　HEAs　that　incorporate　reversible　phase　transformation　(RPT)　mechanism,　facilitating　the　understanding　of　the　evolutionary　processes　governing　mechanical　behavior　at　the　microstructural　level　and　thereby　guiding　the　enhancement　of　toughness　in　B2　lattice　HEAs.　©　2025　Acta　Materialia　Inc.