With the acceleration of global climate change and urbanization, natural disasters have increasingly become a severe challenge to human social and economic development. Cities are the main places where population and economy are highly concentrated, and the harm and loss caused by natural disasters are enormous. Flood disaster is one of the natural disasters with high frequency, wide influence and great harm. With the increasing intensity, frequency and breadth of flood disasters, how to prevent and reduce disasters has become a hot issue of general concern to the contemporary international community. Practice shows that pre-disaster risk management is the most important to effectively resist flood disasters, flood risk assessment is the most important basis for formulating policies and measures for disaster prevention and mitigation, and vulnerability assessment is an important method and means of risk assessment, which has become an important way for international disaster prevention and mitigation. In this paper, the modified SCS model is used to calculate the storm runoff in Pudong New Area in six return periods of 20 years, 50 years, 100, 200, 500 years and 1000 respectively. According to the DEM of Pudong, the submerged depth of Pudong in different return periods is 3.78m, 3.9 1 m and 3. Through grid calculation and reclassification, the submerged bathymetric maps with different recurrence periods are extracted. Combined with the field investigation and referring to the disaster loss rate of foreign natural village houses, farmland, industrial storage, public management and public service land submerged in different water depths, the overall vulnerability grade distribution map of four land types in six return periods is drawn. Through the vulnerability distribution map of six return periods, it is concluded that the vulnerability range and intensity of rainstorm and flood disasters with a return period of 1 .200 years have increased from a return period of 20 years to a return period of 1000 years, and the return period of 200 years is a turning point, which leads to a sharp increase in vulnerability area; The overall vulnerability distribution of Pudong New Area in different return periods is mainly characterized by low vulnerability and high vulnerability, which is related to the scope of vulnerability classification. From 20 years to 100, the distribution range of flood disaster vulnerability is relatively small. Medium-high vulnerable areas are mainly concentrated in Gao Qiao Town, Gaoxing Town, Beicai Town, Zhangjiang Town, heqing town City and Chuansha New City, while low vulnerable areas are distributed near the streets of Pudong New Area and towns in medium-high vulnerable areas. In 2000, 500 and 1000, the vulnerable areas of once-in-a-century floods accounted for 26%, 30% and 32% of Pudong New Area respectively. Medium and high vulnerable areas are mainly distributed in Pudong towns, while low vulnerable areas are generally distributed, but mainly distributed along Pudong streets. 13. the vulnerability analysis of four land types in six return periods is as follows: in six return periods, farmland is always a highly vulnerable area; (2) During the rainstorm period from once in 20 years to once in 100, the land type in the fragile area is natural village houses; The low vulnerable areas are industrial storage, a small amount of public management and public service land and natural village houses; (3) During the return period of 200-1000 rainstorm, the vulnerable areas are mainly natural village houses and a small amount of industrial storage and public * * * management and public * * * service land; The low vulnerable areas are industrial storage, public management and public service land. According to the assessment of the vulnerability of flood disaster in Pudong, this paper puts forward some concrete countermeasures and measures to reduce the vulnerability from three aspects: natural conditions, history and policy.