Abstract: In order to effectively detect cable steel wire damage of long span suspension bridge, the ultrasonic guided wave nondestructive testing technique is investigated by combing theoretical analysis and numerical simulation in this paper. Guided wave dispersion curves in steel wires are obtained by theory to analyze the dispersion characteristics. The L(0, 1) model of the central frequency at 200kHz is selected for the damage detection of steel wires, and the finite element software is used for the comprehensive study of dispersion curves and wave structure. The low order guided wave modes in steel wire are identified by two dimensional Fourier transform technique. Meanwhile, the influence of defect size and angle on the defect reflection coefficient of L(0, 1) mode is analyzed. Finally, the defect signals at the broken positions of two and seven cable steel wires are simulated. The results of the numerical simulation are in good agreement with that of theoretical analysis, which indicates that the low frequency L(0, 1) mode can effectively detect the wire broken damage of cable wires over a long distance.