Virtual manufacturing is a technology facilitating effective development and agile manufacturing of products via sophisticated computer models representing physical and logical schema and behavior of real manufacturing systems including manufacturing resources, environments, and products. For the successful application of this technology, a virtual plant as a well-designed and integrated environment is essential fur sharing information and engineering collaboration among diverse engineering activities. The systematic approaches and effective methods for construction and application of a virtual plant are proposed in this paper, such as a 3-D CAD modeling, cell and line simulations, databases and some information technologies. Measuring and 3-D CAD modeling technologies of many equipments, facilities and structures of the building are developed, and effective information management system managing CAD models, related files and data is implemented in WWW environments. Finally, precise simulations of unit cell lines and the whole plant are performed. For the beginning of implementing a Virtual Automotive Plant, the Virtual Plant fur the Body Shop of a Korean automotive company is constructed and implemented. We could obtain the benefit of savings in time and cost in many manufacturing preparation activities in the new car development processes.