Abstract: To detect the corrosion of load-bearing steel strand, the magnetic memory technology was introduced. Through the corrosion detection test of load-bearing steel strand, the magnetic flux leakage signal of steel strand was analyzed, and the corrosion detection criterion of load-bearing steel strand was constructed based on magnetic flux leakage signal. The results show that with the increasing of corrosion degree, the magnetic flux leakage signal of loaded steel strand is increased, and the tangential component of magnetic induction intensity meets at one point at both ends of the corrosion area with the maximum value in the middle of corrosion. The normal component of magnetic induction intensity has the reverse maximum and minimum values at both ends of the corrosion, which illuminates that the corrosion position and range of steel strand can be determined qualitatively. The relationships among the dimensioned peak value of tangential/normal component of magnetic induction intensity of magnetic flux leakage signal of load-bearing steel strand corrosion, the corrosion degree and the tensile force can be further analyzed. The relationships are distributed in Boltzmann function, which means that the corrosion degree and tensile force of steel strand can be determined quantitatively.