The invention discloses a test system and method for dynamic errors of a mutual inductor. The system comprises a dynamic waveform signal source, a signal processing unit, a standard mutual inductor unit and a dynamic error checking unit. The dynamic waveform signal source is used for simulating various dynamic loads to generate dynamic waveform signals through multiple modes; the signal processingunit is used for generating a processing signal suitable for primary side input of the mutual inductor according to the dynamic waveform signals; the standard mutual inductor unit is used for providing standard mutual inductor output which is used as a comparison object; the dynamic error checking unit is used for conducting error analysis according to the standard mutual inductor output and to-be-tested mutual inductor output at the same input and outputting error data. According to the test system and method, dynamic error tests on the electric mutual inductor when the process is simulatedthat an electric system is connected with the dynamic loads are achieved, and a technical means is provided for evaluating the influence of the dynamic loads on the metering performance of the electric mutual inductor.