Abstract: As an important component of power system construction, the quality of construction and operation level of power transmission and transformation projects are directly related to power supply safety. In view of the problems such as the incomplete index system and the strong subjectivity of the weighting method in the post-evaluation of power transmission and transformation projects, this paper, under the idea of combining qualitative and quantitative methods, constructs a multi-level comprehensive evaluation index system covering the project implementation process, project effect and benefit, and project environmental and social benefit. The AHP method is used to determine the subjective weight, the entropy weight method is used to determine the objective weight, and the combination weight is formed by combining the two. The TOPSIS model is introduced to evaluate the comprehensive level of the project. Taking the actual data of power transmission and transformation projects in China as an example for empirical analysis, the results show that the combination weight can effectively balance the differences between subjective experience and objective data, verifying the scientificity and feasibility of the model. The research conclusion not only provides a method reference for the post-evaluation of power transmission and transformation projects, but also provides reliable support for the management, operation improvement and investment decision-making of power engineering construction.