Watt-hour Meter is the main device in electric energy metering instrument, also is a kind of measuring instrument used in trade settlement. It's accurate and reliable is very important in protecting the interests of users and the electric power enterprise. So it is particular important to verify the Watt-hour meter. In this paper, we introduce the hardware and software of master control part in Watt-hour meter calibration device. We use the ARM9(S3C2440) as the master control part in the device, and adopt Microsoft's embedded system Wince as the operating system, use MFC to develop the user application program. Implement software interface simple and beautiful.