Abstract: In this paper,a new approach of automatic generation of 3-D tetrahedral element mesh based 2-D triangle mesh is presented.The key principle of the algorithm is that the original prismatic polyhedron is formed by planer triangular mesh crossed with vertical section,and then divided into several tetrahedral elements according to the information parameters zonation in aquifers.The moving free groundwater table is also taken into account during the course of mesh generation in each calculation step.The programming procedure of tetrahedral meshing is also stated in detail in the paper.It is concluded that the algorithm is a valid,effective and convenient approach to the description of spatial stratum formation in complex aquifer such as lens or sharp lithofacies and etc,so as to provide 3-D mesh data for numerical calculation1