Abstract: The non-contact surface potential probe is mainly used in the lunar environment simulation laboratory in order to test the potential of the simulated lunar soil. The design is based on the non-contact Kelvin vibrating capacitor principle. The capacitance changes in the mechanical vibration between the probe and the charged surface would induce a current, so the potential of the charged surface can be calculated by measuring this induced current. On the other hand, the piezoelectric ceramics will undergo a deformation under an applied voltage. A sinusoidal voltage signal drives the piezoelectric ceramics to change the capacitance. The instrument is applied in the lunar environment simulation laboratory. The measurement range Can reach 0~4000V and the accuracy can be better than 5%. It can not only be used in the simulation laboratory, but also be used in other surface potential measurements, and eventually in the spacecraft charged measurement in space.