In recent years

building a 3D geological model for water resources and hydropower projects has become a new useful method for geological workers to know layer structure and analyze geological phenomenon. Based on CATIA software

a 3D geological modeling platform is built using Visual Basic.net language

which contains several basic modules

such as overburden layer

geological layer

hydrological layer

model analysis

model cutting

finite element analyses

etc. Based on the 3D geological modeling platform developed by authors

the modeling process for overburden layer is proposed. Some key technology issues are analyzed in detail

such as original data processing

surfaces splitting and surface stitching. Besides

the platforms have the functions of quality testing and repairing work for building 3D geological model which guarantee the reliability of the model. At last

a 3D geological model is built using 3D modeling platform to simulate the geology for a hydropower station. 2D figures can be exported by cutting the model at any angle and anywhere in 3D space to satisfy the designing requirement in engineering.