The Subject of this research is building integrated library to supported to CAAD of the A.E.C field that is oriented to the environment of integrated design. In this research, we design and implement a new library model as a solution of design-data sharing and multi-displaying that is on the rise among many problems in construction integration. We name this integrated library ACO(Actual Component Object) and using the ACO, we can share data without loss in the fields such as construction, estimation, structure. Together with this, the different expressions along each field provide the solution of sharing both graphic data and non-graphic data. This ACO is a newly conceptualized Library that is able to supply a composite structure to an architect(designer) through the internet-based ACO System. To the ACO System that supplies those ACO service, we introduce the concept of DBMS in design and design administrator, and we investigate the solutions that enable an architect to use this ACO directly on the Web.