Abstract：Three-dimensional geological modeling is important for engineering decision，geological analyses and prediction，and improvement of cartographical efficiency. Through an engineering example，the process of establishing a three-dimensional geological model，including data analysis and pretreatment，surface and solid creation，the disposal of the fault，stratum and other factor concerned with the three-dimensional geological modeling，is elaborated. A three-dimensional model suited for engineering project is produced by using GemCom software platform and is examined at last. In addition，the method of adopting Laplace interpolation integrated with the irregular triangle net (TIN) to create a three-dimensional surface，which has much more progress compared with the traditional irregular triangle net，is put forward.
