According to the spatial distribution characteristics of waterway engineering，wide-area waterway engineering is divided into several regions，and the dynamic scheduling is carried out by the data organization technology of three-dimensional scenes in different regions.Plug-in tools are employed for the surface reduction of building information modeling（BIM），which ease the workload of manual surface reduction.In addition，the technology of loading geographical information system（GIS）multi-source data by Unity is proposed to solve the problems in practical project applications，such as loading failure of large-scale three-dimensional BIM + GIS data of waterway engineering in Unity，sluggish rendering，and huge workload of making model lightweight manually.In addition，a roaming system is developed utilizing the Unity engine，which enables the loading of three-dimensional BIM + GIS data of super-long waterway and high-quality roaming visualization.The system is of great value to the promotion and application of BIM technology in waterway engineering.