Abstract: Aiming at the problems of lack of three-dimensional sense and less intuition in two-dimensional scenes of conventional plane topographic maps, this paper proposes a railway 3D large-scale scene construction scheme based on multi-source spatial data, puts forward the technical process of railway 3D large-scale scene construction, as well as the methods of data format standardization, data preprocessing, data lightweight processing and data organization and management. The railway 3D large-scale scene application system is designed and developed, and the system development objectives, overall architecture and system functions are introduced. After practical applications of railway engineering, the railway 3D large-scale scene and its application system can provide railway designers with a more intuitive, comprehensive and real 3D space design scene, meet the needs of railway engineering survey and design work such as 3D virtual survey of lines, professional design verification, 3D display and analysis of schemes, and improve the digital and intelligent level of railway survey and design.