This study aims to design and implement an integrated information retrieval system for the archives in Korea. Particularly, this study is focused on the improvement of the usability of the system. To achieve the goal, this study analyzed the current retrieval systems of national archives and presidential archives in Korea. A new integrated retrieval system, called KAIRS, is designed based on the EAD elements, which is implemented through emulation technic between two retrieval systems. KAIRS showed higher of user satisfaction compared to the existing two retrieval systems in their usability test.