Abstract: In this paper,the optimal allocation model of the whole process from the feasibility evaluation to the optimal allocation decision is established. Based on the source-load matching idea,the model establishes the load matching index of wind-solar combined output;considering the new peak shaving demand caused by grid connection,the carbon reduction benefit of renewable energy power generation,and the penalty cost of electricity abandonment,the average power cost model of wind-solar combined output is constructed.Taking the maximum load matching degree and the minimum average power cost as the optimization objectives,the NSGA-Ⅱ algorithm is used to optimize the capacity allocation of wind and solar installation. The COWA operator is introduced and the game theory method is used to determine the index weight to further optimize the optimization solution set to assist decision making. This paper takes a certain region as an example to verify the validity of the model. The model is suitable for the planning and construction of regional power grid and micro-grid. By optimizing the capacity configuration of wind and solar installation,the matching degree of renewable energy output to load can be improved,and the average power cost can be reduced.