With the intensification of climate change and human activities, the hydrological process in urbanized areas has been greatly affected, the frequency of extreme hydrological events has increased significantly, and the flood disaster has become more and more serious. It is of great significance to explore the role of flood evolution and quantitative driving factors in urbanized areas for urban flood control. Taking the Qinhuai River Basin, a rapidly urbanized area in the lower reaches of the Yangtze River, as an example, this paper analyzed the evolution characteristics of its annual maximum daily runoff from 1987 to 2018, used multiple linear regression method and generalized additive model GAMLSS to identify the impact of potential driving factors on the evolution of annual maximum daily runoff, and quantifies the factors' contribution. The results showed that: (1) Under the background of urbanization, the annual maximum daily runoff of Qinhuai River Basin showed a significant upward trend from 1987 to 2018, with an average growth rate of 14.77 m³/(s·a) and a significant mutation occurred in 2001. (2) the optimal model showed that precipitation in flood season and impervious surface ratio are the key driving factors of annual maximum daily runoff change. The former contributed more than 70%, indicating the decisive role of precipitation change; The contribution rate of impervious surface ratio exceeded 20%, also indicated that the change of underlying surface had a significant impact on the evolution of annual maximum daily runoff. (3) The impact of the rise of impervious surface ratio on the relationship between annual maximum daily runoff and flood season precipitation had increased from 6.7% pre-shift to 10.4% post-shift. Rapid urbanization had significantly changed the relationship between runoff and precipitation in this region. Flood control and disaster prevention will be an important task. This study showed that the evolution of annual maximum daily runoff in the Qinhuai River basin was greatly affected by human activities with urbanization and then the flood risk had increased. The research results can provide some reference for flood control and disaster reduction in urbanized areas.