Abstract: As the complexity of VLSI designs and CAD tools increases, how to manage the design data and standard library data effectively has become an impor tant issue.Aa integrated data management interface(IDMI) is presented in this paper. It organizes data logically and describes data with a defined C-like language, i.e., data description language (DDL).The data transactions of all design tools, such as read, write or transfer, are achieved by the data management interface using the corresponding keywords. Therefore, the design tools are insensitive to data file format, namely, the update of the data file format will not cause the modification of the related interface of design tools. The IDMI can also do the lexical and syntax analysis when a tool is reading a DDL file.IDMI has been implemented on HP82S workstation with C programming language and is working as a part of the framework of the FELLOW system.