Abstract: Geology belongs to the data-intensive scientific. A lot of digital data related to the geological and terrain have been collected and will be update, due to the need of scientific research, to better applied to serve the human activity, the data are more and more examined and expanded constantly, the data's number is increasing. The informatization strategy of the land resources in China has profound significance. This paper focuses on the establishment of the "geological cloud" under the back ground of the big data and the application of the big data to geological field. Big data technology brings new methods and ideas for unstructured, semi-structured geological data. The establishment of geological cloud purpose to explore the application of the core data of geological, find the new information by data mining from the unstructured data, for decision support in land and resources administration.