Abstract: AutoCAD Civil 3D is a construction industry oriented BIM solution, which contains all the functions of AutoCAD, and also integrates the functions of AutoCAD Map 3D. The software realizes 3D dynamic model design and brings convenience for engineering modeling design and engineering work calculation. Aiming at a slag site, we demonstrate the application of this software in water soil conservation design by several key procedures such as establishing original terrain curved surface, design curved surface and forming volume curved surface of triangulation net. By these operations, we summarize the advantages of this software in soil and water conservation design of slag site. The experiences can provide references for the designer mastering the application of Civil 3D in soil and water conservation design.