The invention discloses an active frequency control method for a photovoltaic high-proportion sending end power grid after direct current blocking. Specifically, the method comprises the following steps: carrying out time domain simulation under a direct current blocking anticipated fault in real time by utilizing an online dynamic safety and stability analysis system of a dispatching master station of a grid province company, formulating a control strategy of photovoltaic power generation participating in primary frequency modulation of a power grid, and when the direct current blocking faultis monitored in real time, matching the strategy to enable a photovoltaic power station to participate in the primary frequency modulation of the power grid; in addition, calculating the CPS index ofthe power grid after the direct-current blocking fault in real time, when the index is unqualified, judging whether frequency modulation water and thermal power margins are sufficient or not in realtime, and starting photovoltaic power station coordination to adjust the secondary frequency of the power grid when the frequency modulation water and thermal power margins are insufficient; and whenthe power grid operates stably, reasonably improving the real-time power generation power of the photovoltaic power station according to the transmission margin of the outgoing section. The frequencymodulation capability of the photovoltaic power station can be effectively utilized and is coordinated with conventional water and thermal power, and the safety and the stability of the photovoltaic high-proportion sending end power grid in a large-frequency-difference event are improved.