BIM design is the most ideal mode for the application of BIM technology in the design stage. It is also an inevitable choice to ensure that the drawings are consistent with the model and the design information is smoothly transferred to the construction, operation and maintenance stages, thereby extending to the application of CIM. However, from the enterprise level, the transition from the traditional CAD design mode to the BIM design mode is switching the whole process work mode, which generally encounters great difficulties. Based on practical experience, this paper analyzes and summarizes the key technologies and management points of the design enterprises′ comprehensive transformation to BIM design mode, and proposes a technical route for reference.