In this study, to set the direction of improvement and development Library One Service, a current status survey was conducted for regional centers and libraries participating in Library One Service, and satisfaction surveys were conducted for users. As a result, it confirms that the user had a positive perception of the Library One Service, but there were various considerations and service improvements from the user and manager side. In particular, the need to solve the problem of instability in the middleware server and to revise the regulations, and to expand the user service and support practical work was confirmed. So, this study proposed to improve the function of the Library One Service, provide new services, support policies such as revision of regulations and related guidelines, and provide practical support for a service operation. Through this study, it expects to be able to present a road map for mid- to long-term development of Library One Service.