After the research area is reasonably meshed, geological variables are extracted by using the GIS spatial function. Some which are related to the evidence of the division and classification of the area are selected to outline the background field on the basis of mathematical models. A sample of geological background is shown in Weixi area,Yunnan province. Relationship between known mineral resources and field of geological background is expounded, at the same time relationship between different fields of geological background and mineralization is researched.