Abstract: Existing 3D modeling methods of coal seam use twice interpolation algorithms and traditional triangular prism to construct coal seam model, which lead to bigger error. Delaunay triangle subdivision algorithm and Kriging interpolation algorithm were adopted to establish 2D curved surface data model of coal seam according to drilling data of coal mine in a database, so as to form upper and lower surfaces of 3D coal seam model. An improved triangular prism element was taken as basic element to construct 3D coal seam model combined with 3D drilling model, so as to realize 3D visualization of coal seam and automatic calculation of coal reserve. According to original drilling data of a coal mine, 3D coal seam model in a working face was constructed by use of 3D modeling method of coal seam based on the improved triangular prism element and coal reserve was calculated with a more accurate result of 4.82% than traditional segment method.