In order to realize the goal that the civil unmanned cargo aircraft (UCA) would be controlled by the operator in the ground control station (GCS), the design scheme of the human-machine interface (HMI) for GCS is proposed which integrates the flight instrument and maps. By the way of mixed programming using the tools of GL Studio and VC ++ 6.0, this paper achieves the design of the flight instrument display interface. With the use of VC ++ 6.0 on the secondary development of Google Earth, this paper achieves the design of map display. With UDP transmission protocol, the flight simulation data from the Microsoft simulation flight X is sent to the interface of the display. The test results show that the system can provide complete information for the operator of the ground control station, improve the decision-making efficiency of the operator, and provide a new method for studying the interface efficiency of the ground control station.