Abstract: To correctly identify the spatial layer relationship of roadway and reflect the real-time status of mine ventilation truely and dynamically，based on the in-depth study of all kinds of drawing algorithms and elements of double-line roadway，the technology of automatic drawing two-dimensional ventilation stereogram by “Improved real double-line method” and “Colosed-polyline-hatch method ” or “ lineweight method” are put forward. The principle of two-dimensional ventilation stereogram automatic drawing and the process of using secondary development of AutoCAD based on C# to realize the function of this module are emphasized. The practical application proves that the new algorithm greatly reduces the amount of computation in one-roadway blanking and system diagram expanding into two-dimensional ventilation stereogram，and removes the defects in conventional ones.

Key words: Ventilation stereogram, Automatic drawing, AutoCAD, Secondary development, C# Language, Net API