The purpose of research are to find out the level customers satisfaction especially the services quality at the use of prepaid electricity in PT. PLN (Persero) Rayon Semarang Selatan and to find out variabel having the strongest and the weakest impact value on customers satisfaction at the PT. PLN Rayon Semarang Selatan. The methods in collecting data were doing distributing interview and questionnaire to 100 customers in South Semarang and data were analyzed using quantitative metode analysis. The data used were the primary and secondary data. The variables of this research were dimension of service namely : Tangibility, Reliability, Responsiveness, Assurance and Empathy. The result of the analysis customer satisfaction index shows that the variabel of Tangiblity was 86,65%, the variabel of reliability was 86,14%, the variabel of responsiveness was 79,08%, the variabel of Assurance was 68,43% and the variabel of Empathy was 73,69%. The analysis shows that the value of that customer satisfaction index for dimension assurance is customer felt dissatisfaction with the availability of electrical pulses prepaid sales the position variables on the diagram of cartesians shows that 60,64% all the variables were located on A quadrant.