Considering the consistency in structures and control strategies of the grid-connected photovoltaic inverter and active power filter, a combined control system is proposed. This system can realize both grid-connected power generation and power quality regulation. One new method is proposed based on the traditional maximum power point tracking method, and the flow diagram is given. Based on the proportional-integral control strategy, a modified proportional-integral-resonant control strategy is applied to the combined control system, the advantage of strategy and the calculation method of parameters are given as well. At last, simulation models are built through Matlab, and results show that the structure and control strategy of the system are valid.