From　the　magneto-elastic　effect　principle,　it　is　known　that　diversity　exists　in　the　magnetic　characteristic　curves　of　rode-like　ferromagnetic　material　under　different　extensions,　so　it　can　be　employed　to　develop　a　new　method　for　the　tension　estimation　of　rod-like　structure.　In　order　to　obtain　the　relation　expression　of　magnetic　characteristic　parameters　vs.　tension,　a　magnetic　characteristic　curve　measurement　apparatus　under　force　and　thermal　load　coupling　condition　was　established;　and　the　experiment　study　on　related　influence　factors　was　conducted　The　tension　measurement　accuracy　is　closely　related　to　many　factors,　such　as　the　sensor　structure　and　its　excitation　mode,　the　residual　magnetism　state　of　the　material,　environment　temperature　and　data　analysis　process,　etc.　First,　the　measurement　accuracies　for　pulse　and　alternative　current　excitation　modes　are　analyzed.　It　is　found　that　the　residual　magnetism　state　strongly　influences　the　measurement　accuracy　for　pulse　excitation　mode;　whereas,　alternative　current　excitation　mode　has　excellent　stability　for　repeated　measurements,　which　is　more　suitable　for　the　tension　estimation　of　rod-like　structure.　Second,　through　comparing　the　coefficient　and　sensitivity　obtained　with　curve　fitting,　the　influence　of　the　excitation　magnetic　field　strength　selection　on　the　relationship　equation　characteristic　between　the　magnetic　characteristic　parameters　and　tension　is　discussed.　A　pre-calibration　equation　of　magnetic　induction　strength　vs.　tension　of　pure　iron　rod　is　obtained;　the　R-squared　value　of　linear　fitting　is　0.99　and　the　sensitivity　of　magnetic　induction　strength　to　tension　is　about　-3.46mT/kN.　Finally,　the　magnetic　characteristic　curves　of　the　pure　iron　rod　were　measured　under　different　temperatures.　The　results　show　that　a　nonlinear　relationship　between　the　magnetic　induction　strength　and　temperature　exists.　The　above　research　provides　the　experiment　method　and　technique　for　estimating　the　tension　of　rod-like　structure　in　practical　engineering.　©,　2015,　Science　Press.　All　right　reserved.