The invention relates to a reactive power optimization method for dynamic wattless equipment of a wind power system of a power grid, and belongs to the technical field of power system safety and control. The method includes the steps of calculating the wattless adjusting scope of all wind turbine generator systems and the reactive power adjusting scope of all dynamic wattless equipment in each wind power plant, calculating the result and sending to a wind power pooling station, the wind power pooling station generating N simulation scenes based on the operation states of each wind power plant, calculating the safety margin under the N simulation scenes, fitting the relation between the wattless value adjusting amount of the dynamic wattless equipment and the safety margin of a wind power plant pooling area according to the safety margin of the wind power plant pooling area corresponding to each scene, and finally, calculating the optimal wattless set value of each dynamic wattless equipment under the current state based on the relation between the wattless value adjusting amount of the dynamic wattless equipment and the safety margin of the wind power plant pooling area. The dynamic wattless reservation optimization method can effectively increase the safety margin of a wind power pooling area.