An embodiment of the invention provides a method and a device for controlling an asymmetric power grid fault of a double-fed power generator. The method comprises the steps of firstly acquiring a motor parameter of a power grid line voltage of the double-fed power generator, determining a positive-sequence voltage component and a negative-sequence voltage component of the power grid based on the power grid line voltage, and then determining the correction value of a rotor current given amount based on the motor parameter and the positive-sequence voltage component of the power grid, wherein the correction value of the rotor current given amount corresponds with the asymmetric power grid fault. When the asymmetric power grid fault is determined, objective current ring given current of a rotor is determined based on the rotor active current given amount, the rotor reactive current given amount which are output from a power ring of a converter and the correction value. Obviously, the embodiment of the invention provides the method and the device for controlling the asymmetric power grid fault of the double-fed power generator, wherein the method and the device can realize adjustment to the negative-sequence component of the power grid voltage.