In today competitive market, served services by competitor companies become similar to each other day to day, and it is difficult to surprise customer with supplying fully new service in the long time; because the innovationist services are imitated by competitors fast and supply to the market. Thus, investment in the loyalty customer scope is very useful and profitable for service companies. Loyalty ends to profitability increase through income increase, cost decrease of gain new customers, decreasing in the customer sensitivity to the price, and decreasing in costs of customers familiarize with methods of doing things. In this survey, it is trying to study various attitudes about loyalty customer and to consider relationship between loyalty and some of effective factors on it. Then, it is considered how to faithful customers and supplying programs in this direction. It is used for considering literature, antecedents and backgrounds of the problem, library method and for gathering information about surveying subject, questionnaire among field methods. Based on data from this study, it is found that service quality satisfy customers effectively. In addition, satisfaction, trust and perceived switching cost make customers loyal. Bank has could supply customer satisfaction with serving acceptable services to customers. This satisfaction along with trust and switching cost factors has made customer loyalty.