With the large-scale wind power grid-connected operation, it is difficult to effectively suppress the wind power fluctuation by relying on the traditional generator set alone. It is necessary to adopt the automatic generation control (AGC) to incorporate the wind farm into the power system frequency modulation control to ensure the stable operation of the power system. Firstly, by analyzing the mechanical characteristics of the doubly fed induction generator (DFIG) and taking into account the economical efficiency of wind power grid-connected operation, the wind power fluctuation control of wind turbines under the high wind speed condition and the secondary power frequency regulation of the wind turbine under the low and medium wind speed conditions are proposed. Secondly, the strategy to improve the traditional pitch angle control enables the high wind speed wind turbine to flexibly respond to the grid's dispatch commands. Finally, the simulation of the automatic generation control control model with wind farm built in the 4-machine 2-area system verifies the effectiveness of the proposed control scheme. The wind turbine can respond to the system's dispatching instructions quickly and flexibly, reducing the power exchange frequency and frequency of the tie line exchange. It can also improve the wind turbine absorption capacity and power system stability.