The invention discloses a wind power plant reactive optimization control method considering DFIG reactive output capacity. The wind power plant reactive optimization control method comprises the stepsof obtaining system data and predictive data of each DFIG in a large-scale wind power plant; by combination of a kinetic model of a wind turbine, calculating the active output predictive value of each DFIG; by combination of the DFIG reactive output characteristic, calculating the reactive output upper limit and lower limit of each DFIG; by taking the minimum wind power plant internal active power grid loss, the maximum reactive margin, and the minimum common grid-connected point voltage deviation as the target, establishing a multi-object optimization function; by taking the DFIG reactive output upper limit and lower limit, SVC reactive output upper limit and lower limit and the common grid-connected point voltage deviation as constraint conditions, establishing a constraint condition function; and solving an optimization model formed by the optimization target function and the constraint condition by adopting a genetic algorithm to form the wind power plant reactive optimization control method which can satisfy requirements.