Urban flooding has become a recurrent issue, leading to significant losses for both people and the economy. Enhancing emergency response capability is crucial for effectively managing flood events. This paper taking Xi’an city of China for an example, applying the prevention-preparation-response-recovery (PPRR) theory to structure the assessment into four criterion layers including prevention, preparation, response and recovery. Assessment indicators are selected accordingly. Analytic Hierarchy Process (AHP) method is used to determine the weights of these indicators. Fuzzy Petri Net is used to evaluate the emergency response capacity of flood disasters. The results indicate that Xi'an City’s capacity is at a medium level. Key factors contributing to this rating include the arrangement of disaster prevention projects, implementation of emergency plans, the level of professional skills in disaster relief, and the disaster insurance system. The use of Fuzzy Petri Net proves to be effective in this assessment. The results offer valuable insights for improving urban flood disaster response capacity in Xi'an City, providing guidance for urban planners and policymakers to enhance flood preparedness and response strategies in rapidly urbanizing areas.