Abstract: Aiming at the problem of insufficient primary frequency regulation ability of the power system caused by large-scale photovoltaic grid connection, photovoltaics actively participate in grid frequency regulation is an important means to solve this problem. Firstly, the topology structure and control strategy of two-stage photovoltaic power generation system are introduced. Then, considering that droop control has limited effect on frequency transient regulation of power grid, a frequency regulation control strategy combining model predictive control and droop control is proposed. On the basis of active power reserve, the strategy changes the output increment of droop control by frequency difference and the output increment of model predictive control by frequency deviation rate, so as to change the output power of photovoltaic power generation and make it participate in system frequency regulation. Finally, a simulation model of a regional grid with PV power generation is built on Matlab/Simulink platform, the feasibility and effectiveness of the frequency regulation control strategy are verified. The simulation results show that the control strategy not only regulates the steady state of grid frequency, but also improves the transient and dynamic effects of grid frequency.