The invention discloses an independent micro-grid robust optimization capacity configuration method based on Benders decomposition. According to the technical scheme, the method comprises the following steps: 1) obtaining a topological structure and basic parameters of an independent AC microgrid; 2) expressing renewable energy source output and load uncertainty with an uncertainty set; 3) establishing a bi-level robust optimization capacity configuration model of the independent AC micro-grid, wherein the model comprises an objective function and system and device operation constraint conditions; 4) constructing a feasibility check subproblem and an economic optimality subproblem, and decoupling the subproblems through a Lagrangian dual method to obtain an objective function, constraint conditions and forms of feasible cutting and infeasible cutting after dual; and 5) solving the problem of capacity optimization configuration. The method, considering uncertainty of renewable energy source output, can realize capacity optimal configuration of the independent AC microgrid, and provides guidance and help for reasonable capacity configuration for each unit of the AC microgrid.