Abstract: In view of problem of complex structure and tracking difficulty of harmonic current of existing active power filter, a novel current control strategy of active power filter was proposed. The control strategy does not need load current measurement and harmonic detector, but directly extracts harmonic component at the supply side, and combines with conventional proportional-integral and vector proportional-integral controllers to control current of power gird, so as to realize harmonic compensation. Simulation results demonstrate correctness and validity of the strategy.