The invention provides a high-voltage crossing control method and device under an imbalanced sudden rise of a power grid voltage, wherein the method comprises the steps of: detecting voltage effective values of three power grid lines at a grid connection side of a wind generating set in real time when imbalanced sudden rise of the power grid voltage occurs; if the difference between at least one of the voltage effective values of three power grid lines at the grid connection side and a power grid voltage set value is detected to be higher than a preset threshold, then calculating a reference reactive current value according to the maximum value in the three detected voltage effective values, and calculating an active current value according to the reference reactive current value; and if the calculated active current value is smaller than an active current set value input at the grid connection side at present, then using the calculated reference reactive current value as a reactive current value input at the grid connection side, and using the calculated active current value as an active current set value input at the grid connection side. According to the invention, the wind generating set is enabled to have the fault ride-through capability under the imbalanced sudden rise of the power grid voltage.