Abstract: Power system planning for carbon emission peak and carbon neutrality goals needs to make decisions on system development with the coupling of numerous new security challenges and low-carbon technologies. The roles of various low-carbon technologies in the low-carbon transition of the power system are unclear and cannot be quantified. In this context, it is critical for planners to further understand the reasons why the planning model gives the planning scheme and to clarify the benefits it brings,rather than only providing the optimal planning solution. This paper introduces the concept of quantitative attribution to the field of power system planning, and a quantitative attribution method based on path integral is proposed to analyze the potential benefits brought by various devices. The method is applied to the quantitative attribution analysis of the planning results for the Garver-6bus test system and Northwest China power system for carbon neutrality goals, where the results confirm the feasibility and effectiveness of the proposed method.