Abstract: In the detection of wire rope damage, the structure design of the flaw detector is very important to the detection precision of wire rope damage. The research on the structural parameters and their combinations of the existing electromagnetic wire rope flaw detector is insufficient. In order to solve the above problems, an optimization method of structural parameters of wire rope flaw detector based on orthogonal test is proposed. Based on the theoretical mathematical model of magnetic field distribution of radial magnetic ring and the theoretical model of the equivalent magnetic circuit, the structural parameters affecting the detection precision of wire rope flaw detector are analyzed and obtained. The parameters include the length of the magnet, the thickness of the magnet, the thickness of the armature, the length of the armature and the chamfer parameter. The influence grade and significance of each parameter are studied by the orthogonal test. The influence grade of each parameter factor on the detection precision of the wire rope flaw detector is the thickness of the magnet, the length of the magnet, the length of the armature, the thickness of the armature and the chamfer. The thickness of the magnet, the length of the magnet and the length of the armature have significant effects. These should be given priority when designing the wire rope flaw detector. The thickness of the armature and the chamfer are not significant and can be ignored. The influence of the thickness of the magnet and the length of the magnet is positively correlated with the increase of level. With the increase of the thickness of the magnet and the length (＜70 mm) of the magnet, the detection precision will be significantly improved. The length of the armature shows a negative correlation trend as a whole. The longer the length, the worse the detection precision. According to the analysis results, the optimized values of the parameters of the steel wire rope flaw detector are determined. The magnetic line distribution, the magnetic field distribution and the radial and axial phase magnetic induction intensity distribution of the steel wire rope flaw detector before and after the optimization are compared and verified. The results show that the optimized steel wire rope flaw detector based on the orthogonal test has uniform magnetic flux distribution. The excitation effect of steel wire rope is more than 2 T. The magnetic flux leakage signal is obvious. The damage signal under different phases is quite different. Compared with the steel wire rope flaw detector before optimization, the steel wire rope flaw detector has the following advantages. The magnetic flux leakage intensity is greatly improved. The spatial distribution is obviously improved. The requirements for the position (lift-off value) of the sensor are relatively broad. The radial detection precision is improved by about 40%, and the axial detection precision is improved by about 80%. The perception effect on the damage of the steel wire rope is obviously improved.