Stability against sliding of anchor foundation is a very important factor considered in bridge design. The topography of foundation pit base directly influences shear strength parameters between bedrock and concrete cemented plane. Analysis is performed about foundation pit base at the north anchor of Run-yang bridge in this paper. Based on DTM（digital terrain model）

MapInfo is chosen as development flat-form of GIS and realize three-dimensional visualization of the north anchor foundation pit base by means of third dimension at graphics technique

and then a detailed analysis is conducted of its fluctuation situation by applying powerful function of measurement analysis and information statistics of GIS. The result of analysis can be shown by graphics mode

which can objectively reflect integrated situation of the whole foundation pit base and is convenient for the communication between decision makers and engineers.