Through the Tensile testing, the acoustic emission characteristic parameters of the whole damage process of the steel strand were obtained. The test results show that the correlation point graph of count, energy, duration, amplitude and time is used to comprehensively characterize the damage, which can not only track the whole process of damage, but also accurately determine the broken wire signal, non broken wire signal and broken wire position. It is found that the acoustic emission characteristic parameters of the steel strand are not obvious before the yield deformation, and after the yield stage, The characteristic parameters of acoustic emission gradually increase, and as the fracture approaches, the characteristic parameters of acoustic emission rapidly increase. Finally, the time series fractal theory of acoustic emission characteristic parameters is used to study the damage evolution law of steel strand. In the middle stage of loading, the Fractal dimension changes little. When the crack of steel strand enters the rapid growth stage, the Fractal dimension changes in a "maximum minimum" mode, which can provide a new criterion for the critical damage of steel strand