Abstract With the improvement of monocrystalline silicon material manufacturing technology, PV modules gradually reduce the manufacturing cost. However, the main technical difficulties for solar power system are the optimization problems of grid-connected system. This paper firstly introduced the differences between China and other countries in grid-connected PV power generation area. Furthermore, this paper also mainly researched the modulation method of PV inverter system, as two methods of SPWM and SVPWM modulation grid system modeling and then applied the methods to the three-phase grid-connected PV simulation system. According to the curve of voltage and current output, advantages of SVPWM method can be verified.