Abstract: The paper proposed a control scheme of three-level active power filter based on ip-iq harmonic current detection, fuzzy PI current control and space vector pulse width modulation. It established a mathematical model of the three-level active power filter, and introduced concrete realization of control method of DC-side voltage stabilization and neutral-point potential balancing of the three-level active power filter. The simulation and experimental results show that the three-level active power filter controlled by the scheme has good effect of harmonic compensation, and can stabilize DC-side voltage and capacitance neutral-point potential well.