Abstract: To provide a kind of more advanced，scientific and standard 3D visualization technique and method for open-pit blasting design，the computer aided design process and the mechanism of open-pit blasting are studied in depth.Based on AutoCAD development platform，visual C++ in Visual Studio 2008 environment combining with ObjectARX，secondary development tools of AutoCAD were adopted to develop SMCAD three-dimensional geological model software.Then，3d visualization application software of open-pit mine blasting was produced.The application in No.1 open-pit coal mine of Shenbao energy company showed that the optimal explosion sequence and blasting heap shape were obtained through multiple demonstrations by this software.With strong adaptability and expansibility，this software greatly improved the blasting management level and design efficiency for open-pit enterprises，and shortened the labor intensity of designer，which provides a kind of decision-making basis for effective blasting design and the scientific and standard 3d visualization design of open-pit bench blasting.

Key words: Open-pit, Computer aided design, 3D visualization, Blasting design, C++