The invention discloses an active power filter of a 380V system, including an active filter branch 1, a current sensor CT1 connected to the three-phase current of the active filter branch 1, a current sensor CT2 connected to the three-phase current of the load, a voltage sensor PT connected to the three-phase voltage, as well as a digital signal processor 2 connected to the sasid four components; The apparatus also comprises a display and man-machine interaction control equipment communicating with the digital signal processor 2 through the system bus. The fast response characteristic and the high controllability of the invention have guaranteed the real-time of reactive power compensation; the invention raises the dynamic ability of eliminating harmonic, and reduces the adverse effect to the system electrical energy quality produced after the compensating input; and the invention also plays the role of stabilizing the voltage, compensation of the reactive power, and raising the efficiency factor.