This paper analyzes the features of data for network-supported collaborative design, researches the data transformation, the data transmission and the data transaction of collaborative design. The system configuration and organization mode of dynamic data exchange for network-supported collaborative design are developed, in which, STEP serves as the product data exchange standard, what's more, Object-Oriented Database (OODB) is the kernel database of the system, so that each of the CAD systems can synchronously access the OODB, share and exchange the design information. The STEP-OODB serves as the organizing mode of dynamic data exchange for the network-supported collaborative design based on Internet, which realizes the real-time exchange and consistency of the dynamic data among the cross-platforms and CAD systems.