Abstract: For the geological phenomena that a fault cut through ore-bodies，three-dimensional （3D） geological modeling is usually performed by connecting the outlines on adjacent geological sections with triangular mesh in a straight line in the current，and it is difficult to reflect the spatial morphological relationship of the fault-cut ore-bodies in the 3D visualization model correctly.A surface-solid Boolean algorithm based on the triangular mesh model is proposed.Firstly，the triangle mesh models for the fault-cut ore-bodies are detected，and the topological relationship between the fault plane and the ore-bodies is built；then，the intersection loops are obtained based on the intersection test；finally，the result domain polygon is extracted and triangulated.For the morphological quantitative study of the ore-bodies cut by a fault，two cutting operators named “acquiring the ore-body on the fault plane” and “acquiring the ore-body under the fault plane” are defined respectively，and the final cutting results are acquired by the two operators.The algorithm avoided the operations of tracing intersection lines into loops and inclusion tests between points and polygons in the traditional Boolean operations.Taking Shuiyindong gold deposit in Guizhou Province as the study example，combined with geological interpretation and 3D geological modeling technique，the algorithm proposed in this paper is used to cut the ore-body intersecting with the fault in the deposit. The study results show that the 3D model cutting operating based on Boolean operations can reflect the anastomosis relationship between the ore-body and fault correctly，the reliable reference for the study of quantitative relationship between fault and mineralization distribution is provided.

Key words: 3D geological modeling, Boolean operations, Triangular mesh, Complex ore-body, Cutting operation