Abstract:On the premise of less borehole data, in order to improve the accuracy of small scale 3D geological model, multilayer DEM model using GMS should be established. In this paper, through analysing distribution characteristics of layers under actual condition, the principle of DEM intersection calculation under different data accuracy have been put forward. After modifying the original DEM, importing them into the original model, and interpolating again, 3D geological model has been formed. 3D geological model has the function of cutting section at any position and at any arbitrary angle. Its higher accuracy lay a good foundation for the next step of hydrology simulation.