As always, Luzong ore district, one of most important districts in the middle and lower Yangtze River, is immediate areas of research focus. Understanding the 3D structure, delineating the locations and variations of the intrusions and ore controlling strata in the study area are essential for selecting deep mineral targets. A pilot 3D geologic model, coving an area of about 6574 km2 (81.08 km×81.08 km) and extends to a depth of 5 km, has been constructed by geophysical inversion based on priori information constrained to define the geometry, depth, and physical properties of geological bodies at depths. The 3D visualization of the results assists in understanding the spatial relations between various intrusive units and the ore bearing strata. The model has confirmed most previous knowledge, but also revealed new features of different folds and intrusions、geologic formations of deep rock masses and the spatial distribution of strata, those are important for planning future exploration at large depths. A number of deep targets have also been predicted by combining the conceptual mineralization model in the district with the 3D geological model. Our study demonstrates the potential of using gravity data with geologic constraints to build 3D models in structurally complex areas for the purpose of mineral exploration at depth and under cover.