Abstract: Photovoltaic (PV) grid-connected power system is becoming a hot research area. As the interconnection of the PV arrays and the power grid, the operational characteristics determines the quality of the grid. This paper analyzes the working principle, control strategy and phase-locked loop of the grid-connected inverter. Photovoltaic power generation system analysis and verifies in Matlab / Simulink simulation software. This paper provides a basis for research on photovoltaic grid-connected systems, achieves maximum power tracking effectively and improves the quality of the grid.