As a kind of clean and renewable energy, solar energy has good prospects for development. When accessing isolated grid, large scale integration of photovoltaic power station may cause the issue of low inertia and lack of ability of frequency regulation in power system, affecting the safe operation of the power system. In view of this, the article changes the power control mode of PV station, sets load shedding level and static frequency characteristic of PV station, making the PV station participate in primary frequency regulation of system. Through simulation analysis in PSCAD/EMTDC, photovoltaic power station realizes the function of primary frequency regulation when the load changs, reducing the variation of system frequency and improving the frequency stability of power system, verifying the effectiveness of the method.