Magnetic field amplitude detection is an important method for determining the positioning and corrosion degree of the grounding grid, and the conventional analysis only determines the grounding grid status by collecting single-component signals, which makes the diagnosis results of the grounding grid status susceptible to the influence of the collection process. By considering the single-component sensor device in the attitude deflection during the actual substation detection process, the analysis of the difference between the signals measured by the sensor under different attitude deflections is performed, and the degree of influence of the attitude deflection on the magnetic field amplitude characteristics is determined. Further, by analyzing the calculation error of the attitude angle on the corrosion degree of the ground grid, the correspondence between the sensor attitude and the calculation error of the corrosion degree was obtained. Finally, in order to reduce the influence of the sensor attitude on the detection signal, it is proposed that the detection scheme of measuring the three-component sensor signal and the attitude angle at the same time which could improve the accuracy of the detection system.