In order to obtain the characteristic relationship between the position quantity and the output voltage of the SDMSA type dual magnetic ring magnetostrictive linear displacement sensor, on the self-made sensor calibration test bench, the excitation magnetic field generated by the displacement sensor rod and the bias generated by the double magnetic ring The relationship between the magnetic field and the distance between the double magnetic rings was studied, and the output voltage model of the double magnetic ring magnetostrictive displacement sensor was established. Under the effect of the same paranoid magnetic field, the relationship between the distance between the dual magnetic rings and the output voltage is explored, and the relationship is derived through experiments. The characteristic relationship between the position and output voltage of the dual-magnetic-ring magnetostrictive linear displacement sensor SDMSA is obtained, and the measurement error of the displacement sensor is analyzed.