Ultrasonic　guided　wave　inspection　is　an　effective　non-destructive　testing　method　which　can　be　used　for　stress　level　evaluation　in　steel　strands.　Unfortunately　the　propagation　velocity　of　ultrasonic　guided　waves　changes　due　to　temperature　shift　making　the　prestress　measurement　of　steel　strands　inaccurate　and　even　sometimes　impossible.　In　the　course　of　solving　the　problem,　this　paper　reports　on　quantitative　research　on　the　temperature　dependence　of　ultrasonic　longitudinal　guided　wave　propagation　in　long　flange　steel　strands.　In　order　to　achieve　the　generation　and　reception　of　a　chosen　longitudinal　mode　in　a　steel　strand　with　a　helical　shaped　surface,　a　new　type　of　magnetostrictive　transducer　was　developed,　characterized　by　a　group　of　thin　clips　and　three　identical　permanent　magnets.　Excitation　and　reception　of　ultrasonic　guided　waves　in　a　steel　strand　were　performed　experimentally.　Experimental　results　shows　that　in　the　temperature　range　from　-4　degrees　C　to　34　degrees　C,　the　propagation　velocity　of　the　L(0,　1)　mode　at　160　kHz　linearly　decreased　with　increasing　temperature　and　its　temperature　dependent　coefficient　was　-0.90　(m　.　s(-1)　.　(C)(-1))　which　is　very　close　to　the　theoretical　prediction.　The　effect　of　dimension　deviation　between　the　helical　and　center　wires　and　the　effect　of　the　thermal　expansion　of　the　steel　strand　on　ultrasonic　longitudinal　guided　wave　propagation　were　also　analyzed.　It　was　found　that　these　effects　could　be　ignored　compared　with　the　change　in　the　material　mechanical　properties　of　the　steel　strands　due　to　temperature　shift.　It　was　also　observed　that　the　longitudinal　guided　wave　mode　was　somewhat　more　sensitive　to　temperature　changes　compared　with　conventional　ultrasonic　waves　theoretically.　Therefore,　it　is　considered　that　the　temperature　effect　on　ultrasonic　longitudinal　guided　wave　propagation　in　order　to　improve　the　accuracy　of　stress　measurement　in　prestressed　steel　strands.　Quantitative　research　on　the　temperature　dependence　of　ultrasonic　guided　wave　propagation　in　steel　strands　provides　an　important　basis　for　the　compensation　of　temperature　effects　in　stress　measurement　in　steel　strands　by　using　ultrasonic　guided　wave　inspection.