Focusing on the issue of assessing and prospecting ore resource, the author has dived into the research on the basic theories and implementing methods of the 3D digital modeling and characterization of mineral deposit and the 3D quantitative prediction of concealed ore body. By taking the Dingjiashan deposit in Fujian, the research assimilates modern theories and methods of quantitative appraisal of mineral resources, 3D geoscience modeling, 3D GIS, etc and proposes a technical system of 3D quantitative prediction of concealed ore body.