Abstract: BIM is the abbreviation for Building Information Modeling.It is the latest industry transformation from the architectural CAD technology based on two-dimensional expression of points, lines, and planes to the new technology represented with object-based three-dimensional shape and attribute information.The research on BIM technology is becoming the most attractive area on the application of information technology in Architecture, Engineering and Construction (AEC) industry around the world.This paper describes the relationship among CAD, BIM and collaboration in AEC industry.It is proposed that the goal, core, and foundation of BIM technology are three key issues which require a deep understanding and cannot be avoided for the BIM research and application.The relevant work carried out by the BIM research team of Shanghai Jiao Tong University is further introduced.Finally several problems and outlook on the current research and application of BIM are summarized.