Abstract: Jingtianlutu is a comprehensive road design platform based on a 3D GIS system. To enable users to accurately express their design concepts and ideas during the use of the software, it is necessary to develop drawing functions with precision requirements in a 3D Earth environment. In this study, based on the LocaSpace development toolkit of Tuxin, the drawing function of basic primitives (points, lines, polylines, circles and arcs) and special points (endpoints, intersections and vertical feet among the primitives) are developed on the platform of Visual Studio 2019 by using C# language. This study introduces the research and development content, detailed design ideas, development tools, development process, and key algorithms behind the drawing functions. Finally, it demonstrates the practical application of the drawing functions and the implementation of the capture functionality. The results show that the basic drawing function developed in this article can conveniently, quickly, and accurately help users express design concepts and ideas, and improve design efficiency.