The purpose of the research are: to know how the customers perception of service quality prepaid electricity at PT. PLN (Persero) Rayon Semarang Selatan and prepaid electricity service quality variables what is a priority for customers. The variabels are Tangible, Reliability, Responsiveness, Assurance, and Emphaty. The sampling technique used is random sampling method. Data collection methods are observation, questionnaires, and literature. The results showed that the customer perception of service quality of prepaid electricity at PT. PLN (Persero) Rayon Semarang Selatan included in the category of medium, and the variable is a priority for customers is Reliability with the highest average scores is 3,46.