Starting from the development of informationization engineering of geological and mineral resources, analyzing the significance of realization of digital geological mapping, combining with the characteristics of geological prospecting and development, this paper introduces methods, workflow, innovative achievements and application signification of CAD technology in digital geological mapping in detail, describes application methods and development trend of digital geological mapping on the basis of “3S” technology, and concludes the workflow of digital geological mapping combining with above technologies, discusses the direction to research and development of digital geological mapping technology systems in the future.