The utility model discloses a synchronous monitoring system for partial discharge of multiple electric power devices of a transformer substation. The synchronous monitoring system comprises a high-frequency shielding bus ring, a single-channel data acquisition unit and a plurality of sensing terminals, the high-frequency shielding bus ring is provided with a plurality of parallel connection points, the single-channel data acquisition unit is connected with the high-frequency shielding bus ring, and the sensing terminals are respectively parallelly connected with the high-frequency shielding bus ring at the parallel connection points. Each sensing terminal comprises an ultrahigh-frequency sensor, an ultrahigh-frequency wide band amplifier, a detector and a high-frequency signal isolator, wherein the ultrahigh-frequency sensor correspondingly receives a partial discharge signal of the corresponding electric power device, an input end of the ultrahigh-frequency wide band amplifier is connected with the ultrahigh-frequency sensor, an input end of the detector is connected with an output end of the ultrahigh-frequency wide band amplifier, an input end of the high-frequency signal isolator is connected with an output end of the detector, and an output end of the high-frequency signal isolator is connected to the corresponding parallel connection point. Each parallel connection point is correspondingly provided with a first path and a second path, and differential values of the first paths and the second paths corresponding to the parallel connection points are different. The monitoring system is capable of monitoring the multiple electric power devices in a high-reliability and low-cost manner.