In order to improve the emergency response capacity of urban flooding disasters, an emergency response capacity assessment model based on the combination of improved DS evidence theory and FBN was proposed. Firstly, from the whole process of disaster emergency management, the urban flood disaster emergency response capacity assessment index system was established and mapped into a Bayesian network (BN) model. Then, to address the problems of information uncertainty and strong subjectivity in the assessment process, the improved DS theory was introduced to determine the index weights. The expert knowledge combined with the fuzzy set was used to quantify the prior probability of the root node. The accident tree was applied to analyze the key indexes, and the Sorting center of mass method was used to assign basic event probabilities. The probability of flooding disaster risk was calculated through the BN model. Emergency response capacity assessment and reasoning analysis were carried out on the basis of the above results. Finally, take the main urban area of Zhengzhou city as an example, GeNIe4.0 software was used to generate the BN model of emergency response capacity assessment of flooding disaster, and the emergency response capacity level and sensitive indexes of flooding disaster in the city were obtained. The results show that the emergency response capacity of the main urban area of the city is good. The sensitive indicators affecting the emergency response capacity are timeliness of the emergency response, normality of the warning information release, professionalism of the emergency response and accuracy of flooding information feedback.