Abstract: To implement united use of heterogeneous databases. The system function layer is composed of transaction logic components, which are designed and developed on the basis of COM/DCOM. ASP is used to call components and manage Web pages of clients. And MTS is in charge of administration of components. As a result GSQL language is provided for users and heterogeneity of local databases is shielded with use of GSQL. Parallel processing is implemented in UUHDB. And the system design and implementation based on COM/DCOM component model is feasible and effective, especially for expanding use in more information sources.