Human resources are the fundamental and critical in maintaining a company competitive advantage, and performance evaluation are the foundation and an important tool in human resources management. Staff performance appraisal can not only improve the core competitiveness of enterprises, make the transformation of business strategy implementation come true, but also be able to ensure the enterprise connect short-term objectives and long-term goals together ,thus becoming the effective means for the enterprise survival and development in a competitive environment. With the constant deepening reform of the electricity system, great change have taken place in the grass-roots power company environment and will hugely continue, so it is urgent for the grass-roots power company to set up an effective staff performance appraisal system so as to continue to improve the performance level of employees and organizations. So it can gain competition advantages in electricity market, seize opportunities and achieve sustainable development in the future.　　Based on the Shaanxi Provincial Power Supply Corporation "321" development strategy, considering MT Power Supply Bureau as the main research object,, applying performance appraisal theory the MT Power Supply Bureau staff performance appraisal system was eventually built and modified. This article first understand and research the relative performance appraisal theory and methods, focused on the theory and application of performance appraisal of the status quo and development trends both at home and abroad, make a survey on the performance appraisal system of MT Power Supply Bureau through a questionnaire, make a comprehensive analysis of MT Performance Evaluation of Power Supply Bureau staff the status quo, found the problem of the performance appraisal questions. Secondly, based on the root causes of specific problems for the previous research, this article conduct further research and discusses setting up the Power Supply Bureau MT performance appraisal system - understand the purpose, principles and steps of performance appraisal systems, and complete the design of performance appraisal index system. Again, using Analytical Hierarchy Process (AHP) determine the weights of indicators, and drawing on the power system performance evaluation results and the units of the new features, the staff to work evaluation scale was designed, and based on comprehensive evaluation theory, the MT Power Supply Bureau performance appraisal fuzzy hierarchy comprehensive evaluation model was set up; Finally, this article give the related measures of the appraisal system.