Augmented reality technology was invented for military purposes at the beginning. But the development of wireless and location based technology in 2000s makes AR services reach the age of innovation. Especially, it attracts attention as a media which enriches our perception. There is a potential that it can extend the virtual information in the real world from optical sense to auditory, tactile, and olfactory sense. This study proposed the interactive information service system and method based on AR. To do it, technical background on AR was analyzed and a method to apply the technology was examined. Especially, as a eco service, this study proposed new information service using 2D bar code in a library for user need and convenience in ubiquitous environment. The proposed service system can optimize practical utilization of information resources in virtual and real reality as consolidating analog and digital resources in a library.