Taking geological exploration engineering as the topic of our research, we presented a hybrid data model integrating vector and raster data, and proposed a sub-model; i.e., a QTPV (Quasi Tri-Prism Volume) model. Based on QTPV, the concept model, logical model and data structure were designed in detail. Modeling, model cutting and partition algorithms on QTPV are proposed. The modeling features of QTPV have been discussed. The QTPV model is more efficient than 3D FDS and TEN in terms of partition, storage volume, modeling ability, and application in Geological Exploration Engineering (GEE). A 3DgeoMV system prototype has been developed based on the proposed QTPV model. A case study has been conducted by using the real borehole sample data from a GEE area in China's Inner Mongolia China. The application shows that the QTPV has the ability to model real 3D in GEE.