The invention discloses a system and a method of detecting partial discharge in equipment, aiming to solve the problems of worse detection accuracy of discharge types inside equipment and failure on effectively inhibiting various interferences in a detection environment in the prior art. The method of detecting partial discharge in equipment comprises the following steps: simultaneously detectinga UHF signal generated inside the equipment from two positions; computing the ratio of two pulse amplitudes of each group in multi-group synchronous pulse in the UHF signal detected from the two positions; and outputting the phase-amplitude relationship of the UHF signal according to a plurality of the ratios. By adopting the technical proposal of the invention, discharge types of multi-source discharge inside the equipment can be distinguished.