The invention relates to a Facts equipment compensation method for improving static safety margin under the condition of N-1, and belongs to the technical field of power systems. The method achieves the judgment of nodes under the worst conditions through employing the selection and comparison of margin of a power system under the condition of N-1, obtains the site selection and constant volume of Facts equipment for compensation, and achieves a purpose of improving the static safety margin of the power system. The method specifically comprises the steps: selecting a node load as a margin index of a node, calculating margin indexes under all conditions of N-1, and finding out the worst condition and the worst node; obtaining a node with the maximum participation factor in the power system through comparison according to the size of participation factors of all nodes, and enabling the Facts equipment to be placed at the node with the maximum participation factor; solving a model formed by the above target function and constraint condition through a fixed point traversing method, and obtaining the constant volume of the Facts equipment. The method can improve the static safety stability of the power grid in the most effective manner, and is of great significance to a power grid operation dispatching department and the planning of the power grid.