With the acceleration of urbanization and the effects of global climate change, urban flooding has become increasingly frequent. Based on an extensive literature review, a vulnerability index system comprising seventeen indicators was constructed to assess urban flooding vulnerability in thirteen prefecture-level cities in Jiangsu Province. The combination weighting method based on game theory was applied to determine the vulnerability levels. The results indicate that torrential rainfall frequency, value added of the tertiary industry, GDP per unit land area, population density, urbanization rate, impervious surface ratio, and per capita road area are key indicators in evaluating vulnerability. Rapid economic development coupled with relatively outdated urban planning concepts are major factors contributing to urban flooding vulnerability. The southern region of Jiangsu is the most vulnerable, followed by the central and northern regions. The study further proposes targeted strategies to help mitigate urban flood risks and enhance resilience in vulnerable regions.