Abstract: The large-scale grid integration of wind power reduces the equivalent inertia and increases the uncertainty of the power system, which brings challenges to load frequency control (LFC). The potential frequency regulation capability of the voltage source converter based high voltage DC (VSC-HVDC) was taken into consideration, and a load frequency control strategy for the virtual synchronous generator (VSG) with variable parameters was proposed when the wind farms was connected to the power grid by VSC-HVDC. Firstly, based on the analysis of the LFC model and the topological structure of the grid connection of wind farm connected by VSC-HVDC, the VSG control method was designed for the voltage control process of voltage source converter (VSC) in order to improve the controllability of VSC-HVDC. Then, the correlation relationship between VSG control parameters and frequency changes was analyzed. Based on the fractional-order gradient descent method (FOGDM), the deep frequency change characteristics were extracted by using the fractional-order derivative of frequency to optimize the control parameters of VSG. Based on the results above, the uncertainty of the system was taken into consideration, and a trigger mechanism was designed to adjust the VSG variable parameter optimization method, which could reduce the frequency of parameter transformation and improve the control pertinence. The simulation results show that the proposed method can be adopted to effectively improve the load frequency control effect of power grid and has good adaptability.