<正> In the CSR control system, we used COM to exchange data with device. It collects data, analyses the data and send data to user. Here we introduce the COM's implementation in the vacuum control system. The COM implements the interface between WDM device driver(.sys) and MCGS Driver(.dll). The COM can provide us with many advanced features. Many kinds of programming windows language allow calls to a DLL, including VB, C/C++, and Delphi.