For a long time, the study of 3D geological modeling relies on using exploration data from drill holes or geologic sections. But, on the premise of the lack of large area general geological background modeling, only considering of local region refined modeling often lead to overgeneralization and over-reliance on the data. Plane geological map, which integrates geological field survey and the results of the work with geological expert knowledge, reveals rock stratigraphy and geological structure of the region, is the available and the most direct data source for 3D geological modeling. On the premise of the lack of other geological data, using planar geological map to build 3D geological model is an effective solution. The 3D geological modeling directly based on planar geological map, but it is weak in controllability and the building quality of the geological models is unsatisfactory. To solve this problem, this article proposed a new 3D geological modeling method based on geological plane maps and used cutting profile as the intermediary. The method encrypted the existing data of the study area indirectly, processed complex structures such as folds using cubic spline fitting combining with artificial revision, and realized the automatic drawing of cutting profile based on the geological plane maps. We took regular voxels as the 3D spatial data model, got a series of parallel cutting profile of the study area automatically drawn, and built a rasterized 3D geological model. With Xinggang area, Chongqing City as the study area, the prototype experiment system was built and we verified the effectiveness and practicality. Results showed that the 3D geological modeling method based on geological plane maps is an effective solution to build regional 3D geological model under the condition of lacking of other geological data.