Abstract: Power grid performance study is an important tache for power supply companies, and it works important to improve the company development. It has an important meaning not only to advance and perfect the decision-making, also to support electric network reconstruction and benefit of investment. Along with the reform of economy system, market economy has more and more restriction to the investment. Besides, as the gradually growing of electric market, electric company will take more care of the network performance evaluation. Power network performance evaluation is the premise and foundation of overall economic efficiency analysis. Regarding on the appraisal to the power grid performances, it is helpful to appraisal its own management capability correctly and understand its own exists insufficiency, so it can discover the disparity and formulate the effective management developmental strategy. Power supply companies shall establish a scientific, practical and accurate performance evaluation model. The research on the selection indexes and assessment method should be able to fully reflect the current state, planning strategy and promoting development of the power grid. In this paper, based on the model of evaluation index system, we analyzed the performance of the grid and established the hierarchical structure model. This model has a classified hierarchical structure, it consist of power supply capability improving, voltage quality improving, reliability improving, etc. Most indexes of this model are quantitative which come from actual operation data, so as to make sure that the evaluation is objective. Using the analytic hierarchy process (AHP) to analyze the weight of index system in order to acquire the performance coefficients. These can objectively and factually reflect a power network production operation condition as well as its effect on the local power network. This paper has guiding significance and reference value for self evaluation by power supply companies and post-evaluation by third independent institution.