With the continuous development of offshore wind power, the proportion of wind power installed capacity in the system is getting larger, which has a serious impact on system frequency security. To this end, this paper establishes an offshore wind power grid-connected system frequency model including active frequency control link based on the traditional power system frequency response model (SFR). This model includes a reduced-order model of wind farms with different wind conditions, and wind turbines operate in load-shedding status, this model can provide frequency support when disturbance occurs, and can ensure the safety and stability of the system frequency. Then use MATLAB/Simulink simulation to compare the detailed model and reduced-order model of the frequency response of low wind speed, medium speed and high wind speed wind turbines to verify the effectiveness of the reduced-order model. The results show that the model can effectively simulate the frequency response characteristics of wind turbines.