In recent years, with the growing scale and maturing technology, photovoltaic power generation has been supported by governments and become the main force of low-carbon energy development. At the same time, the reactive power reversal brought by photovoltaic power generation also brings new pressure and challenges to the power system. On the basis of Changxing power system structure and common control schemes, the characteristics of photovoltaic cells are studied by Matlab/Simulink simulation, and the reactive power of power grid during the Spring Festival is analyzed. Finally, the principle and control strategy of photovoltaic grid - connected control are analyzed in detail, which can effectively improve the reactive power level of power grid, reduce power system losses and save transmission costs, laying a solid foundation for the future construction of ubiquitous smart grid.