An alignment determines the distribution of stations, bridges, tunnels, and subgrades following some predefined codes. Alignment interactive design is the precondition for alignment optimization. When an engineer trying to design an alignment, the preparatory work is the data preparation and understanding of the geographical environment. Alignment interactive design is a design-evaluation-redesign process based on the geographical environment. Generally, there are three desired capabilities of a software program for alignment interactive design. Firstly, it can integrate multi-source data inside a three-dimensional (3D) scene, including terrain data and various feature data of geographical objects. Secondly, it not only supports the alignment interactive design in the traditional two-dimensional (2D) manner but also expresses the real spatial alignment and the related sketches of civil structures for intuitive analysis. Thirdly, it can calculate the quantities of civil work and other indexes supporting the automatic alignment evaluation. This chapter introduces how to make a program for alignment interactive design through osgEarth and Qt integration to realize the above operations.