The objective of this study was to identify and evaluate the attributes of electricity supply services in Ninh Hoa Electricity, the Electricity Corporation of Khanh Hoa. Method of group discussion experts and customers in-depth interviews were used to develop a list of attributes that the customer and the electricity supplier trust is important when using electricity supply services in Ninh Hoa Town. Convenience sample of 394 customers to use electricity for the purpose of family activities and 152 customers use electricity for other purposes in the town of Ninh Hoa, Khanh Hoa province has been collected. Customers are asked to rate the importance of the quality attributes and the level of performance attributes in a detailed questionnaire. Through analysis importance - performance analysis (IPA), the results were tabulated to compare, evaluate the strengths and weaknesses of the service quality attributes power supply. Research shows that IPA provides a useful method for assessing the properties reflect the quality of service provided electricity.