Abstract: With the outbreak of the energy crisis and the increasingly serious environmental problems, the development and utilization of renewable energy has become the core issue of the strategic transformation of energy in the world. Renewable energy is gradually becoming an important source of new type power, in the meantime the structure and operation mode of power grid will undergo major changes. By the end of 2017, the installed capacity of China's grid integration wind power has reached 164 million kilowatts, and the total capacity of solar photovoltaic (PV) power generation has reached 130 million kilowatts. PV power generation system is integrated into power grid by means of power electronic converters, and usually does not participate in frequency and voltage regulation when operating according to the maximum power point tracking (MPPT) mode, nevertheless, when the capacity of the grid is more than a certain scale, especially for the high penetration renewable energy integrated system, renewable energy is required to participate in frequency and voltage regulation to ensure the safety of power system. In order to make full use of the active function of the PV power unit itself, a decentralized frequency regulation strategy for PV plant is proposed based on droop control idea in this paper. The active power regulation value, as an additional active power reference, is obtained according to the frequency regulation coefficient of PV unit; then the active power output of the PV unit is quickly regulated to the reference value, so that the frequency recovery of power system is restored. Since each PV unit in the power plant can achieve frequency regulation directly through the change of terminal frequency value, the response time will be faster than other control modes. Finally, a PV power plant which adopts the decentralized frequency regulation system is modelled on the DIgSILENT PowerFactory platform, and the control effect of the decentralized frequency regulation is verified by simulation results under different disturbances.