Abstract: To facilitate the access to product data in a distributed heterogeneous environment, we designed a SDAI C late binding system with Client-Server architecture. The system is comprised of a data dictionary, an interface layer, an object management subsystem and a database abstract layer. The data dictionary maintains the information of EXPRESS schemas in a computer manageable manner. With its support, the interface layer and the object management subsystem can cooperate with each other to implement remote and concurrent access to STEP data, real-time transaction management, as well as the interface to STEP data views. The database abstract layer is responsible for performing all operations on underlying databases and hiding the differences between various DBMS's from other subsystems. The prototype has been applied to distributed data access in GS-ICCC, an integrated CAD、CAPP、CAM system.