The invention provides a system and a method of measuring performance of a partial discharge transient state ground voltage detector. The system comprises a signal generator, a coaxial cable 2, a metal board, a matched resistor 4, a TEV (Transient earth voltage, transient state ground voltage) sensor 5, the transient state ground voltage detector 6 and a signal cable 7, wherein the signal generator is a sinusoidal signal generator 1 or a pulse signal generator 8, and the signal generator is connected with the metal board through the coaxial cable 2. The transient state ground voltage detector 6 is connected with the TEV sensor 5 through the signal cable 7, the TEV sensor 5 is tightly attached to the surface of the metal board which is grounded through the matched resistor 4, and the signal generator and the grounded end of the transient state ground voltage detector 6 are directed grounded. According to the fact that types or amplitudes or sizes of signals generated by the signal generator are regulated, linearity errors, pulse counting testing errors, stability errors and location functions of the transient state ground voltage detector 6 are tested. The test method is easy to achieve and simple and rapid to debug, and achieves process digitization.