In this article, two BIM applications of the United States were selected to present how to use BIM to reduce building energy consumption and to realize the "Digital Factory". In the first case, how to use BIM techniques to simulate building energy consumption was presented. A series of energy efficiency measures have been proposed and also quantified. The results from BIM energy simulation show that total energy cost will be reduced by at least 20% if appropriate measures are taken. The second case presented how to use BIM to realize the digital factory. This project was for ongoing operations and maintenance and the overall design process should allow access to facility-related data from many sources, including the existing documents, models, and drawings. Owner group, WFG facility management, knew well how they pre-set for this project and played an appropriate supporting role to provide all fundamental data and standards for efficient workflow.