Abstract: Objectives: The construction of effective path set is the key link of traffic control and guidance of highway network, and plays an important role in post disaster path planning. Usually when a disaster occurs, there is a problem that the current emergency route planning does not incorporate the dynamic changes of disasters in time, which affects the subsequent emergency evacuation and rescue and relief. Method: To solve this problem, a double-layer road network model is proposed, which couples the topological structure of the highway network with the traffic flow and the state of disasters and events. The linear reference and dynamic segmentation technology are introduced to associate the routes and events and the DFS (Depth First Search) algorithm is improved based on Dijkstra algorithm. Result: (1)For the double-layer road network model, it reflect the topological relationship between the road sections, store the dynamic attribute information of the road sections and realize the search and construction of effective path sets.(2)For DFS algorithm after improved, it reduce the computational complexity and propose an effective path search algorithm combining time-varying road network, disasters and traffic conditions. Conclusion: The example application and verification in the study area show that the method can dynamically search the effective path set according to the time-varying traffic conditions and disasters. This model enhances the expression and analysis ability of road data, can serve the traffic analysis and control under the change of disaster situation, and is suitable for the post disaster traffic operation situation assessment of road network.