The utility model relates to a novel three-phase four-wire system electric power active filtering device. The device comprises a three-phase IGBT inverter bridge circuit, a DSP main control circuit, avoltage and current signal acquisition circuit and a three-phase four-wire power supply. wherein the three-phase IGBT inverter bridge is connected with the power supply side three-phase voltage and neutral line, the current transformer is connected with the power supply side three-phase voltage and neutral line, the load side current, the filter side three-phase current, the neutral line upper current and the power supply side three-phase current, and the voltage transformer is connected with the power supply side three-phase voltage; the input end of the PLL module is connected with the power supply side three-phase voltage; the output end of the ADC module is connected with the DSP main control circuit, and the output end of the PLL module is connected with the DSP main control circuit;and the DSP main control circuit is connected with the three-phase IGBT inverter bridge circuit through the drive circuit. The utility model has the characteristics of flexible control, flexible configuration and good filtering effect, improves the power supply quality, is beneficial to energy conservation and environmental protection, and can be widely applied to reactive compensation and harmonic suppression of a low-voltage power distribution system.