An　innovative　method　is　presented　for　tensile　force　measurement　based　on　the　notch　frequency　property　which　is　a　inherent　character　of　longitudinal　guided　wave　in　strands.　To　test　the　relation　between　notch　frequency　and　tension　in　different　strands,　a　flexible　low　frequency　transducer　is　designed,　which　can　excite/receive　L(0,　1)　mode　guided　wave　in　a　frequency　range　of　30　kHz　to　160　kHz.　Notch　frequency　property　is　tested　on　two　strands　with　different　diameters　of　17.8　mm　and　15.2　mm　respectively,　and　the　characteristic　frequency　is　found　to　be　linear　to　the　Napierian　logarithm　of　tension　and　the　ratio　of　two　side　peak　of　the　notch　frequency　is　improved　linearly　by　increasing　the　tension.　The　change　of　acoustic　characteristic　parameter　including　the　characteristic　frequency　and　the　ratio　of　two　side　peak　caused　by　1　kN　tension　increment　corresponding　to　3　MPa　stress　increment　can　be　detected,　and　the　change　conform　to　the　calibration　relationship　equations.　Within　the　rated　working　load　scope,　the　relative　error　of　tension　estimation　is　less　than　1.5%,　so　that　the　presented　method　can　be　applied　for　highly　precise　tensile　force　measurement.　According　to　the　experimental　conclusion,　a　modifier　formulas　of　the　center　notch　frequency　of　L(0,　1)　mode　guided　wave　connected　with　tension　in　strands　is　obtained.　The　innovative　method　is　easy　to　operate,　and　therefore　it　has　good　prospects　for　engineering　applications.　©　2016　Journal　of　Mechanical　Engineering.