Abstract: The construction of mountain expressways faces challenges such as complex terrain, information islands and insufficient dynamic control, and the traditional management mode is difficult to meet the needs of high-precision collaboration. In this paper, the integration of BIM and GIS technology is used as the core to build an intelligent management platform for mountain high-speed construction. By unifying the coordinate system and semantic mapping rules of BIM (IFC standard) and GIS (DEM, lidar point cloud, oblique photography model), the problem of data heterogeneity is solved. The three-layer architecture of "data-service-application" is designed, and the spatial analysis engine, lightweight rendering, and real-time data synchronization mechanism are integrated to realize the linkage simulation and risk warning of construction progress-environment Key technologies include BIM-GIS data conversion algorithms, WebGL accelerated rendering, and cloud collaborative computing frameworks. The research results show that the platform can break through the limitations of traditional two-dimensional management and control, support three-dimensional path planning, conflict detection between proposed structures and original terrain, and dynamic optimization of resources, and the research results provide theoretical support and technical paradigm for the digital management of traffic engineering in complex terrain, and promote the intelligent transformation of infrastructure.