Be aimed at the complex of the system structure and the circuit composition, and the low linearity and sensitivity of LVDT used in industrial testing, design a hollow LVDT, use the DC constant current as its excitation signal, and the ARM microcontroller controls the switch bridge to charge or discharge the original coil. During the stable discharge period, the microcontroller control logic is used to capture the pulse height difference between the two secondary coils to measure the displacement. The final test data show that the full scale of the hollow LVDT designed by this method is 3mm. The relative percentage accuracy is 0.3%, the sensitivity is 0.284 words / µm, and the high frequency response characteristic,which can meet the general industrial automatic control and measurement requirements.