Abstract: The Global Position System become the important data sources of Geographical Information System for theprecise position data it provide, and it is more broadly useful in life and scientific research.
The method is implermenting of serial port comnunication by programning in Visual basic or C+ +, thereare two different ways to do it, one is the method that creat a application by VB or VC receiving and processingGPS signal, then send signal to GIS to display in a DDE conversation; the other is the method that creat a DLLfile can be call in GIS, or creat a software which has entire funtion to receive and display GPS signal on the baseof gis control; they are only formally different. In addition, some source codes for implementing the function arealso presented in this paper.

Key words: Global Position System, Communication of Serial Port, Visual Programming language