With the increasing scale of large public buildings and the increasing time of indoor activities, the demand for indoor navigation services is growing. To fill the gaps of current indoor navigation system, this paper uses the rich 3D information which included in the building information model to build a BIM-based indoor navigation system for large venues. This paper designs the overall system architecture for indoor navigation system and achieves the functions of 3D map display, cross-floor indoor navigation and simulation navigation by using four modules: map management, positioning management, path planning and background management. It was specifically implemented in an international expo center navigation project. The system can satisfy the demand for indoor navigation services for large venues, while storing and analyzing navigation data, which can promote the development of smart parks and smart cities.