The invention discloses an internal model control method for a fixed pitch wind turbine, which belongs to wind power generation system control technology. The method compensates the disturbance of pneumatic torque by reconstructing an inverse formation internal model controller of a model, thereby ensuring the stability of a wind turbine when the wind turbine works above rated wind speed, namely works in a deep stall region. The variable speed control is performed on the fixed pitch wind turbine within the whole designed wind speed range, and the rotating speed of the wind turbine is adjusted by controlling the electromagnetic torque of a generator to achieve the aim of power control of the fixed pitch wind turbine; and the method improves the utilization efficiency of wind energy, overcomes the disadvantage that the fixed pitch wind turbine has poor output power characteristics above rated wind speed, solves the stability problem when the wind turbine operates in an unsteady torque area, and ensures that the wind turbine cannot run away or be shut off due to external disturbance.