In order to effectively utilize solar energy and alleviate the pressure of the power supply, this paper put forward a scheme which suitable for household 3 kW singlephase gridconnected photovoltaic inverter system. The main components parameters of each part of circuits were determined by theory analysis and calculation. And double closed loop control system was designed using the current tracking control strategy. The model of whole system is presented by MATLAB. Simulation experiments proved that this system could rapidly track the maximum power point in the case of light disturbance and the output current of this system could change to follow with power grid voltage. Two parameters keep the same frequency and same the phase. The whole system achieved high power factor to the grid.