For nonlinear load capacity in power grid rising sharply, the single phase full bridge combined shunt active power filter (SAPF) is introduced in this paper. The simulation and analysis has carried on in this paper, also a shunt active power filter system with a maximum compensation current of 100A used in the three-phase four-wire networks has designed and implemented, which is mainly counteract the harmonic current with a equal amplitude and opposite polarity compensation current, so as to filter harmonics current in power systems. And the paper’s major work is related to the designs of the system’s hardware and software as well as the collaborative work between the various modules within the system.