Objective Current research on vulnerability assessment of urban road networks primarily focuses on static network vulnerability， neglecting dynamic impacts. This study effectively evaluates the dynamic vulnerability of cascading failures in urban traffic networks considering traffic flow redistribution.Method Based on multi-dynamic passenger flow loading and redistribution， an L-space method topological structure for urban road networks is constructed， and a failure propagation mechanism is introduced to simulate network paralysis resulting from traffic flow redistribution after single to multiple node failures， focusing on the formation and spread of cascading failures.Result The study proposes a comprehensive traffic performance evaluation index and a road network functional vulnerability index ， comprehensively assessing the performance and functional vulnerability of road networks under cascading failures from a dynamic perspective.Conclusion The research findings provide a theoretical basis for road network vulnerability assessment， aiding relevant departments in optimizing and managing traffic on congested roads， controlling cascading failures in road networks， and efficiently evacuating traffic in a prioritized manner.