Abstract: Based on the structure of the flood vulnerability, 11 indexes are chosen to establish the flood vulnerability evaluation index system. Then the regional flood vulnerability evaluation method based on catastrophe theory is established and applied to evaluate the flood vulnerability of the Huaihongnanpian (HHNP) flood protection area, which is a national key flood protection area. The results show that the flood vulnerability degree is high in most areas of the HHNP flood protection area. The townships with the first level of flood vulnerability are Toupu, Mohekou and Caolaoji, with the second level of flood vulnerability are Daxin and Xinji, with the third level of flood vulnerability are Xinmaqiao, Wangzhuang, Caoguzhangxiang, Wuxiaojie and Kuainan, with the fourth level of flood vulnerability are Xiaobengbu, Meiqiao and Linbeihuizu, with the last level of flood vulnerability are Huaiyuanxianchengguan and Weizhuang. And compared with the fuzzy optimization method based on entropy weight, the results of the two evaluations are basically the same, which further demonstrates the rationality and effectiveness of the method. The research results have a guiding role in reducing the flood vulnerability of each township in the flood protection area, which is of great significance to the flood disaster reduction investment and flood disaster management.