With regard to the different capacity power source inverters in parallel, a dual-outer-loop distributed control strategy is proposed. It can achieve the goal that the required modules in parallel system depend on the value of load current and all the parallel modules share load current in proportion to their own capacities, in addition, restrain circulating current and realize the redundancy in parallel. In this strategy, each inverter has three loops: an inner-loop current controller is used to improve the system dynamic response, an outer-loop voltage controller is to govern system stability, and an outer-loop current controller can achieve a weighted output current by following the output signal of power distribution unit. In order to realize load current accurately distribution and redundancy control of system, power distribution unit provides the given current signal of current outer-loop and switch signal of all modules according to the value of load current and voltage source rated current. Theoretical analysis and simulation verify the effectiveness of the strategy.