Abstract: A new strategy for unified control of grid-connected photovoltaic and active power filter is presented. Taking a distributed small-capacity inverter as the research object, the harmonic and reactive power current are detected based on the theory of instantaneous reactive power. By using SPWM current vector control technology, the proposed control strategy is simulated and verified in the MATLANB/SIMULINK simulation environment. The simulation results show that the control strategy can guarantee the grid-connected system with maximum power, make full use of the inverter capacity, and realize such functions as the load harmonic, specific harmonic elimination and optimal reactive compensation, which improve the utilization of equipment and power quality.