Based on the principle of inductive sensors measure magnetic core displacement, using SCM and FPGA as control core, the sinusoidal signal generated by the DDS is amplified, differential coupling the signal through the differential transformer, the two rectified output signals are amplified, then data is collected and processed, achieving accurate measurement of magnetic core displacement. This device measures the displacement range which is from -20mm to 20mm, measurement error is not more than 0.5mm, the waveform of C point without distortion, the DC waveform of A and B point without fluctuation, and use DC motor to drive magnetic bar move, control the magnetic bar to set the displacement, displacement measurement error is not more than 0.5mm. It uses liquid crystal display and keypad to achieve the human-computer interaction. In addition, the system takes various anti-jamming measures to improve the operation of the system stability