Abstract: This paper examines the control strategies of a two-stage three-phase photovoltaic (PV) grid-connected system. In the front-end circuit, the incremental conductance method is used to track the output power of the PV array, while a Boost converter regulates the DC voltage. In the rear-stage DC-AC conversion, a dual closed-loop control with a voltage outer loop and a current inner loop stabilizes the DC voltage and enables unity power factor grid connection. A system simulation model was built in MATLAB to verify the MPPT algorithm, Boost converter control, and inverter control strategy. Results show that the system can track the maximum power point effectively and achieve high-quality grid connection, offering theoretical and practical insights for optimizing two-stage three-phase PV grid-connected systems.