A city three-dimensional foundation information consultant system is developed to manage the foundation engineering data. Using the geotechnical random field model, it can predict unknown geotechnical parameter. Spatial database of the system is designed in details. The relationship of all needed information database, including physical relation and logical relation is built. The application of the database makes dynamic multi-way inquiry, statistics and prediction of geotechnical parameters into realization. The output predicted graph database can provide a good policy-making support service for the city foundation information management.