Abstract: The levitation gap sensor of high-speed maglev train provides necessary gap information for the levitation control system. While the relative position sensor provides secondary phase angle and velocity information for the traction and operation control of high-speed maglev train respectively. Based on an analysis of their application differences, the common technologies like detection coil design, circuit structure design, dynamic characteristics, antielectromagnetic interference and anti-temperature drift are discussed. For the levitation gap sensor, the cogging effect should be weakened, while for the relative position sensor, it is necessary to strengthen the cogging effect, in order to suppress the fluctuation of levitation gap and reduce the degree of signal distortion when the sensor passes through the joint.