Abstract: In order to analyze the section of reconstructed tissues and observe the inner tissues in multi-tissue reconstruction and visualization, the 3D model is cut by plane or polyhedron. Lists of edge and vertex in every cut plane are established. From these lists the boundary contours are created and their relationship of enclosure is ascertained. The region enclosed by the contours is triangulated using Delaunay method. The cut model still maintains its correct topological structure. With these operations, inside tissues can be observed easily and it can help doctors to make diagnosis.