Abstract: As the largest source of carbon emissions,the power industry plays an important role in achieving the goal of carbon peaking,and power planning is the key path to regulate carbon emissions. To this end,considering the difference of utilization hours and coal consumption rate of coal-fired power units with different capacities,this paper proposes a calculation method for the total annual CO₂ emission of coal-fired power units,and establishes a multi-objective optimization model of generation expansion planning for provincial power grid under the constraint of carbon peaking. The model takes the minimum total investment cost of the system and the minimum CO₂ emission in the planning period as the dual objectives,and introduces constraint on the year when the carbon peak is achieved. Then,a multi-objective optimization model solution method based on Monte Carlo simulation and NSGA-Ⅱ is proposed to generate the Pareto optimal solution of the multi-objective configuration scheme of power planning. The proposed method is used for power planning of a provincial power system in China,the results verify the rationality and effectiveness of the proposed method.