Abstract: The traditional methods of external transportation planning and design of hydropower projects are cumbersome and complicated, poor visualization and lack of systematic theoretical models. In view of above challenge, based on the engineering background of Xulong Hydropower project, this paper designs a route optimization system for external transportation of hydropower station by combining the map web API technology, WebGIS technology and optimal path algorithm. Firstly, aiming at the route optimization problems of multi-source, multi-path and multiple transport methods in Xulong Hydropower Project, we establish a multi-source and multi-layer path optimization model with user-defined optimization objectives, and use the optimal path algorithm to solve the model. Then a programming language is applied to realize the model, and an automatic acquisition method and data management mode based on Baidu map API is given, and a visualization scheme by combining the WebGIS technology is proposed. The application results show that the system can realize a whole automation process from data acquisition to scheme optimization, and the GIS-based scheme visualization.