Rectangular　tube　as　an　atypical　waveguide　structure,　the　propagation　characteristics　of　the　guided　wave　in　it　are　more　complex,　and　it　is　not　easy　to　use　its　specific　mode　for　detection.　In　order　to　realize　the　in-service　detection　of　the　rectangular　tube　structure　stress,　the　acoustoelastic　properties　of　the　SH0　modal　of　the　horizontal　shear　wave　are　calculated　based　on　the　characteristic　frequency　method.　The　numerical　simulation　is　used　to　verify　acoustoelastic　constant　and　experimental　feasibility.　According　to　the　experimental　loading　conditions,　the　stress　distribution　of　axially　drawn　rectangular　tube　is　analyzed　by　using　finite　element　method　to　reasonably　arrange　the　SH0　mode　EMAT　sensor.　The　experiment　on　the　acoustoelastic　constant　of　rectangular　tube　subjected　to　different　tensile　stress　is　carried　out　on　a　self-made　tensile　platform.　The　experimental　results　show　that　the　ratio　of　the　test　acoustoelastic　constant　to　the　theoretical　calculation　result　for　SH0　mode　in　rectangular　tube　is　0.592　6,　and　it　is　weakly　affected　by　the　texture　effect　of　material.　According　to　the　results　of　the　stress　evaluation　error,　it　is　found　that　the　SH0　mode　error　is　larger　in　the　low　stress　region.　When　the　stress　is　lower　than　100　MPa,　stress　deviation　is　generally　above　20　MPa,　whereas　the　deviation　in　the　high-stress　region　can　be　stabilized　at　about　10　MPa.　The　results　show　that　whether　the　stress　of　rectangular　tube　structure　is　overloaded　can　be　estimated　based　on　the　SH0　mode　acoustoelastic　effect.　©　2019　Journal　of　Mechanical　Engineering.