In order to assess mineral resource， it is necessary to study a lot of ge ochemical data.Recently the geographical information system (GIS) as a good spatial data analysis tool has been widely used in the geochemical data study all over the world. GIS can supply us many useful functions such as the management of geochemical data, mapping of geochemical anomalies and visualizing of geochemical data mining process. GGCAS（GISBased Regional Geochemical Data Processing System）try to combine traditional geochemical data processing with GIS in order to construct a friendly visual geochemical data processing system.